PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

PSEB Solutions for Class 7 Science Chapter 7 Weather, Climate and Adaptations of Animals to Climate

Science Guide for Class 7 PSEB Weather, Climate and Adaptations of Animals to Climate Intext Questions and Answers

Think and Answer (Textbook Page No. 75)

Question 1.
Name the instrument used to measure relative humidity.
Answer:
Wet Bulb and Dry-bulb thermometers.

Question2.
Which instrument is used to measuring rainfall ?
Answer:
Rain gauge.

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

Question3.
Name the source you used to collect weather reports ?
Answer:
Weather data was obtained from the North Meteorological Department’s laboratory.

1. Fill in the Blanks:

(i) …………………. of a place may change during a day.
Answer:
Temperature

(ii) The areas of Earth near North Pole and the South Pole are called ……………….. .
Answer:
Polar Region

(iii) The amount of water vapours present in air is called ……………… .
Answer:
Humidity

(iv) ……………….. is the coldest desert on earth.
Answer:
Antarctic

(v) Indian hot desert or Thar Desert spread over states of ………………… and ……………….. .
Answer:
Rajasthan and Gujarat.

2. State True or False:

(i) Reindeer is the main animal of tropical forest.
Answer:
False

(ii) Weather and climate both terms have same meaning.
Answer:
False

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

(iii) Camel stores fat in its hump which is consumed during the days it does not get food.
Answer:
True

(iv) Whale is the largest animal.
Answer:
True.

3. Match the Columns ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
(i) It insulates its body and keeps the polar beer warm (a) Land breeze
(ii) This instrument is used to measure humidity in air (b) Hot and dry.
(iii) Imaginary lines on the earth parallel to the equator (c) Fat layer under the skin
(iv) Cood air that blows during day towards coastal area (d) Dry and wet bulb thermometer.
(v) The climate of Rajasthan is (e) Latitude.

Answer:

Column ‘A’ Column ‘B’
(i) It insulates its body and keeps the polar beer warm (c) Fat layer under the skin
(ii) This instrument is used to measure humidity in air (d) Dry and wet bulb thermometer.
(iii) Imaginary lines on the earth parallel to the equator (e) Latitude.
(iv) Cood air that blows during day towards coastal area (a) Land breeze
(v) The climate of Rajasthan is (b) Hot and dry.

4. Choose the Correct Answer:

Question (i)
Weather of a place is affected by:
(a) Wind
(b) Temperature
(c) Humidity
(d) All of these
Answer:
(d) All of these.

Question (ii)
Climate of coastal areas is:
(a) Hot to dry
(b) Moderate
(c) Cold and dry
(d) Extreme cold
Answer:
(c) Cold and dry.

Question (iii)
The coldest desert on earth is:
(a) Arabian desert
(b) Sahara desert
(c) Thar desert
(d) Ladakh
Answer:
(b) Sahara desert.

Question (iv)
Arctic region lies at:
(a) 23°
(b) 23°
(c) 0°
(d) 85° N to 90°S
Answer:
(d) 85° N to 90°S.

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

5. Very Short Answer Type Questions:

Question (i)
Name any two factors that affect the weather of a place.
Answer:
Factors affecting the weather of a place are:

  1. Sun,
  2. Wind,
  3. Water / Rain/ Moisture,
  4. Temperature,
  5. Distance from sea or ocean.

Question (ii)
Define climate.
Answer:
Climate. An average of 25 to 30 years of weather conditions in a place is called climate.

Question (iii)
What is sand dune ?
Answer:
Sand dune. When the wind blows, the sand flies from one place to another. When the wind stops blowing, the sand falls in one place and collects to form low hill structures. These are called sand dunes. They are usually found in desert areas.

Question (iv)
What is a polar region ?
Answer:
Polar Region. The region near the North Pole and the South Pole of the Earth is called the Polar Region. The north snow is centred on these poles. The in the north it is located at Arctic Ocean and in the south it is located at the Antarctic Continent. It is very cold in these areas all the time.

6. Short Answer Type Questions:

Question (i)
How does sea breeze occur ?
Answer:
The earth heats up faster than water during the day. The air near the bottom of the earth gets warmer and lighter and rises upwards. The air above the sea compared to the air above the earth is cold and heavy. So the wind blows toward the earth. The cool breeze that blows from the ocean to the earth during the day is called sea breeze.
PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate 1

Question (ii)
Write three adaptations found in aquatic animals.
Answer:
Adaptations found in aquatic organisms:

  1. Streamlined body which helps in swimming.
  2. Gills, they can take oxygen in the water.
  3. The presence of fins helps in swimming.

Question (iii)
What is green house effect ?
Answer:
Green house Effect. Infrared and ultraviolet radiation are present in sunlight. The ozone layer of the atmosphere absorbs the ultraviolet radiation but the infrared radiation reaches the earth. Some of these radiations are reflected and absorbed by carbon dioxide. Because the infrared rays have heat, the absorbed radiations heat up the atmosphere. This effect of carbon dioxide is called the green house effect.

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

Question (iv)
Write two effects of climate change.
Answer:
Effects of climate change:
1. Global warming. Deforestation and combustion of fossil fuels increase the percentage of carbon dioxide in the air. Carbon dioxide gas acts like a glass house and absorbs infrared radiation from sunlight, which raises the temperature. Due to this the green house effect is increasing.

2. As a result, glaciers are melting. Glacier melting alarm for aquatic life. Melting ice raises sea levels, endangering many coastal cities.

7. Long Answer Type Questions:

Question (i)
How is camel adapted to survive in hot desert ? Explain.
Answer:
PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate 2
The adaptation of the camel to live in the desert:
The camel’s physique and habits have made it adaptable to the hot and dry climate of the desert.
The following adjustments are found in the camel:

  1. Its feet are flat to walk on the sand.
  2. Its nose is covered with nasal membranes so that sand does not enter the nose.
  3. It drinks a lot of water when available. This water spreads to the tissues of the body, which helps the camel to stay without water for many days.
  4. It accumulates fat in its mouth. When food is not available to it, it uses this fat.
  5. Very little water immerses through the urine.
  6. Its long legs keep it high above the hot sand.

Question (ii)
Name various factors that affect the climate of a place. Explain any two of them.
Answer:
PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate 3
Factors affecting the climate of a place:

  1. Distance from sea level
  2. Direction of mountains
  3. Distance from the equator
  4. Height from the sea.

1. Distance from the sea level.
The climate of the places near the sea is pleasant. During the day the temperature of the earth is higher while the water of the ocean warms up relatively late. The wind blows from the bottom of the ocean towards the earth, which is called sea breeze. The earth cools faster than water at night. So the air above the oceans is hot and light and the air above is moving towards the ocean. The cold breeze that blows toward the sea at night is called the land breeze.

2. The direction or latitude of the mountains.
The shape of the earth is not completely spherical. It is slightly raised near the equator. As a result, the sun’s rays are directed closer to the equator. The latitude of the equator is 0° and it is higher towards the pole. The longitude of the North Pole is 90° N and the longitude of the South Pole is 90°S. The climate near the equator is hot and humid all year round. As the longitude increases, the climate cools down.

Question (iii)
Write various adaptations found in Polar beer.
Answer:
Adaptations in Polar bear. The following adaptations are found in polar bears:

  1. Its fur is white to camouflage with snow capped areas.
  2. Its long hairs protect it from extreme cold of cold climate.
  3. A thick layer of fat deposit under the skin helps to keep it warm.
  4. Its feet are so shaped that it can run easily on snow.

PSEB Solutions for Class 7 Science Weather, Climate and Adaptations of Animals to Climate Important Questions and Answers

1. Fill in the blanks:

(i) The average weather taken over a long time in called ……………. .
Answer:
climate

(ii) A place receives very little rainfall and the temperature is high throughout the year;
the climate of that place will be …………… and …………….. .
Answer:
Hot, dry

(iii) The two regions with extreme climatic conditions are ……………… and ………….. .
Answer:
Polar, Tropical Rain forests

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

(iv) The maximum temperature of the day occurs generally in ……………..
Answer:
Afternoon

(v) ………………. is used to measure rain.
Answer:
Rain gauge

2. Match the Column ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
(i) The coldest desert on earth (a) Moisture
(ii) The amount of water vapours in the air (b) Deforestation and burning of fossil fuels
(iii) Thar desert (c) Antarctica
(iv) Global warming (d) Rajasthan.

Answer:

Column ‘A’ Column ‘B’
(i) The coldest desert on earth (c) Antarctica
(ii) The amount of water vapours in the air (a) Moisture
(iii) Thar desert (d) Rajasthan
(iv) Global warming (b) Deforestation and burning of fossil fuels.

3. Choose the Correct Answer:

Question (i)
What is the cause of change in weather?
(a) Moon
(b) Planet
(c) Satellite
(d) Sun.
Answer:
(d) Sun.

Question (ii)
Indicate the type of climate in Jammu and Kashmir.
(a) Hot and wet
(b) Hot and dry
(c) Moderately hot and moderately wet
(d) Wet.
Answer:
(c) Moderately hot and moderately wet.

Question (iii)
Indicate the type of climate in Kerala:
(a) Hot and dry
(b) Hot and wet
(c) Wet
(d) Moderately hot and moderately wet.
Answer:
(a) Hot and dry.

Question (iv)
From where do we get daily weather report ?
(a) Television
(b) Radio
(c) Newspaper
(d) All of the above.
Answer:
(d) All of the above.

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

Question (v)
When is the minimum temperature likely to occur in a day ?
(a) Evening
(b) Early morning
(c) Noon
(d) None of the above.
Answer:
(b) Early morning

Question (vi)
Maximum temperature of the day occurs generally in:
(a) When the sun rises
(b) In mid noon
(e) Afternoon
(d) When the sun sets.
Answer:
(e) Afternoon.

4. State True or False:

(i) All changes in weather are due to the sun.
Answer:
True

(ii) The highest temperature of the day is in the evening.
Answer:
False

(iii) Different places have the same temperature.
Answer:
False

(iv) Polar areas are located near the Poles.
Answer:
True

(v) Penguins live in the plains.
Answer:
False

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

(vi) Days in winter are shorter in length.
Answer:
True

Very Short Answer Type Questions

Question 1.
From where do we get daily weather reports ?
Answer:
We get weather report from Television, Radio and Newspapers.

Question 2.
Which factors are responsible for weather ?
Answer:
Temperature, Humidity and Rainfall.

Question 3.
What is humidity ?
Answer:
Humidity. It is the measure of quantity of moistures present in the atmospheric air.

Question 4.
Which department is responsible for preparing weather reports ?
Answer:
Meterological Department of the Government.

Question 5.
Which instrument is used to measure rain fall ?
Answer:
Rain gauge.

Question 6.
Do maximum and minimum temperature remain constant over a week ?
Answer:
No.

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

Question 7.
Where from do we get heat and light on the earth ?
Answer:
We get heat and light from sun.

Question 8.
What happens to the energy emitted by sun ?
Answer:
It is absorbed and reflected by the earth’s surface.

Question 9.
Climate is average weather report of a place taken over a long period. How long this period is ?
Answer:
About 25 years.

Question 10.
Which type of climate is found in Kerala ?
Answer:
Hot and wet.

Question 11.
What is typical desert climate ?
Answer:
Hot and dry.

Question 12.
Which part of India is wet ?
Answer:
North-East.

Question 13.
Why is adaptation by animals necessary ?
Answer:
For survival of animals.

Short Answer Type Questions

Question 1.
Name the elements that determine the weather of a place.
Answer:
Elements of Weather:
Temperature, Humidity, Wind-speed, Rainfall.

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

Question 2.
When are the maximum and minimum temperature likely to occur during the day?
Answer:
Maximum temperature of the day occurs generally in the afternoon while the minimum temperature occurs in the early morning.

Question 3.
What is rain gauge ?
Answer:
Rain gauge. It is an instrument used to measure rainfall. It consists of a .measuring cylinder and a funnel on the top to collect rainwater.

Question 4.
Define weather ?
Answer:
Weather. The day-to day condition of atmosphere at a place with respect to temperature, humidity, wind speed etc. is called weather.

Question 5.
The tropical rainforest has a large population of animals. Explain, why it is so ?
Answer:
Tropical rainforests have hospitable climatic conditions; so it has a large population of animals. The climate in this region is hot and humid. It lies around the equator and has minimum temperature a little higher than 15°C, length of days and night are generally equal and these places recieve a lot of rainfall. So all these conditions are preferable for a large number of population.

Question 6.
What is cold desert region ? How does polar bear adapt the condition to survive in this region.
Answer:
Those region/area where temperature may fall below-20°C and rocks are stony and have little vegetation are called cold deserts. In India cold desert lies between Ladakh region in north to Lahaul and spiti valley of Himachal Pradesh. To survive in cold desert, Yak has following adapations:

  1. Body is covered by long hair or fur.
  2. The colour of fur is generally black to absorb more and more heat.
  3. Its feet have sharp toes which help it to climb in uneven paths.
  4. A layer of fat is deposited under its skin. It helps yak to survive in extreme cold during winters.

Long Answer Type Questions

Question 1.
What is the condition of tropical rainforests ? What type of animals are living in such rain forest ? Write down the main characteristics of these animals.
Answer:
Tropical rainforest. The area near or around the Tropic of Cancer and the Tropic of Capricorn is called the tropical area. The climate in these areas is hot and humid. Here even in winter the temperature is 15°C and in summer the temperature reaches 40°C. The tropical region receives rainfall throughout the year. The most prominent places of the tropical region are the tropical rainforests that form canopies over the area. Elephants, tigers, leopards, snakes, birds and insects are the animals found in rain forest.

Main Characteristics of animals found in rain forest:

  • Creeping, snakes, lizards, monitor can easily crawl in dense forests.
  • Strong body. Strong body is required to pass through dense forests. So Elephants, gorillas, tigers, leopards, etc. have powerful bodies.
  • Special Senses. Many tropical animals have sharp eyesight, sharp hearing and some animals have skin color similar to surroundings for camouflage.
  • Strong tail
  • Loud voice
  • Sharp eyes
  • Fruit diet
  • Long and big beaks.

Question 2.
Discuss the human activities responsible for climate change.
Answer:
Human activities responsible for climate change are as follows:

  • Population Growth. Consumption of fossil fuels is increasing due to population growth and changes in living standards.
  • Deforestation. Large scale deforestation is done to meet the needs of the growing population such as houses, buildings, industries, roads etc.
  • Excavation of mines. Excavation of blind mines has increased floods.
  • Global warming. Due to excessive cutting of trees and burning of fossil fuels the percentage of carbon dioxide increases. This carbon dioxide gas absorbs infrared radiation from sunlight, resulting in a rise in temperature. As a result, the green house effect continues to grow and as a result glaciers are melting.

PSEB 7th Class Science Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate

Weather, Climate and Adaptations of Animals to Climate PSEB 7th Class Science Notes

  • The weather of a place changes day by day and week by week.
  • The weather depends on temperature, humidity and rainfall.
  • Humidity is a measure of water vapour in the air.
  • Indian Meteorological Department of weather forecasting, daily collect statistical data of heat, wind speed at various places and makes weather predictions.
  • Atmospheric conditions in terms of temperature, humidity, rainfall, wind speed, etc. of a place is called the weather of that place.
  • The weather can change in an instant.
  • Factors on which the weather depends, these are called elements of weather.
  • Special high-low thermometers are used to measure the temperature. The highest temperature of the day is usually in the afternoon and the lowest is normal usually in the morning.
  • All changes in the weather are caused by the sun.
  • In winters, the length of the day is shorter and the night is earlier.
  • The length of the weather of a place is based on the data collected at that place is called the climate of that place.
  • The climate of different places is different. It changes from hot and dry to hot and humid.
  • Energy reflected and absorbed by the earth’s surface, ocean and the atmosphere play important roles in determining weather at any place.
  • Climate has a great impact on living things.
  • Animals are adapted to the conditions in which they live.
  • The Polar Regions are located near the poles, such as the North Pole and the South Pole.
  • Canada, Greenland, Iceland, Norway, Sweden, Finland and Alaska and Siberian areas of Russia in America, are the Polar Regions
  • Tropical rainforests are found in India, Malaysia, Indonesia, Brazil, Republic of Congo, Kenya, Uganda, and Nigeria. The Polar Regions have a cold climate.
  • Rainfall is measured by an instrument called the rain gauge.
  • Penguins and polar bears live in Polar Regions.
  • The Polar Regions are covered with white ice.
  • The white hairs on the polar bear’s body help protect it and catch prey.
  • Penguins are well known animal found in Polar Regions. It is also white and merges well with the background.
  • In addition to polar bears and penguins, many other animals are found in Polar Regions.
  • Many fishes can live in cold water.
  • The climate of the Subtropical Regions is generally warmer, as these areas are closer to the equator.
  • Temperatures in these regions vary from 15°C to 40°C.
  • In areas near the equator, the length of night and day is approximately equal throughout the year.
  • Weather: Everyday changes in the atmosphere in terms of temperature, humidity, rainfall, wind speed, etc., is called the weather of that place.
  • Climate: The average weather pattern taken over a long time, say 25 years is called the climate of the place.
  • Adaptation: The special characteristics of plants and organisms, that is, the nature that enables them to live in a habitat, is called adaptation.
  • Migration: Moving from one place to another to avoid harsh climatic conditions by birds and animals is called migration.

Punjab State Board PSEB 7th Class Science Book Solutions Chapter 7 Weather, Climate and Adaptations of Animals to Climate Textbook Exercise Questions and Answers.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

PSEB Solutions for Class 7 Science Chapter 5 Acids, Bases and Salts

Science Guide for Class 7 PSEB Acids, Bases and Salts Intext Questions and Answers

Think and Answer (Textbook Page No. 54)

Question 1.
What will be the colour of basic solution after the addition of pehnolphthalein ?
Answer:
Adding phenolphthalein to the alkaline solution turns its colour to pink.

Question 2.
Name the products of neutralisation.
Answer:
In the process of neutralisation salt and water are produced in the form of products.

PSEB 7th Class Science Guide Acids, Bases and Salts Textbook Questions and Answers

1. Fill in the blanks:

(i) Acids are …………….. in taste.
Answer:
sour

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

(ii) Litmus and turmeric extract are …………….. indicators.
Answer:
natural

(iii) Phenolphthalein is ………………………… in acidic solution.
Answer:
pink

(iv) Reaction between an acid and a …………………… is called neutralisation reaction.
Answer:
alkali (Base)

(v) Ant’s sting has ………………….. acid.
Answer:
formic

(vi) Excess secretion of hydrochloric acid in stomach, is called ……………………….. .
Answer:
indigestion

(vii) Milk of magnesia is used in case of ……………………. .
Answer:
acidity

2. Match the Column ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
1. Red litmus changes to blue in (a) Neutralisation
2. Blue litmus changes to red in (b) Zinc Carbonate
3. Reaction between acid and a base (c) Basic solution
4. Formic acid (d) Antbite
5. Calamine (e) Acidic Solution

Answer:

Column ‘A’ Column ‘B’
1. Red litmus changes to blue in (c) Basic solution
2. Blue litmus changes to red in (e) Acidic Solution
3. Reaction between acid and a base (a) Neutralisation
4. Formic acid (d) Antbite
5. Calamine (b) Zinc Carbonate

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

3. Choose the Correct Answer:

Question (i)
Vinegar contains :
(a) acetic acid
(c) citric acid
Ans.
(a) acetic acid .

Question (ii)
Tamarind contains :
(a) acetic acid
(b) lactic acid
(c) citric acid
(d) tartaric acid
Answer:
(d) tartaric acid

Question (iii)
The example of natural indicator is
(a) Litmus
(b) Turmeric extract
(c) China rose petals
(d) All the above
Answer:
(d) All the above

Question (iv)
The colour of blue litmus in acidic solution in :
(a) purple
(b) blue
(c) red
(d) pink
Answer:
(c) red

Question (v)
Amla contains :
(a) ascorbic acid
(b) quick lime
(c) calmine
(d) All the above
Answer:
(a) Ascorbic acid

4. Write True or False:

(i) Citric acid is found in tamarind.
Answer:
False

(ii) Ant’s sting has oxalic acid.
Answer:
False

(iii) Turmeric extract gives reddish brown colours in basic solution.
Answer:
True

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

(iv) Sodium hydroxide turns blue litmus red.
Answer:
False

(v) Organic matter is used to treat acidic soil.
Answer:
False

5. Very Short Answer Type Questions:

Question (i)
Which acid is secreted in our stomach ?
Answer:
Gastric acid is excreted in our stomach.

Question (ii)
Name any two ant acids.
Answer:
Names of two antacids :

  1. Magnesium Hydroxide,
  2. Baking Soda.

Question (iii)
What type of substances are used as ant bites ?
Answer:
Solution of calamine or baking soda is used to treat ant-stings.

Question (iv)
Name any two citric fruits.
Answer:
Names of Citrus Fruits :

  1. Orange,
  2. Lemon,
  3. Grapes.

Question (v)
Why is it essential to treat acidic products ?
Answer:
Factory and industry residues are naturally acidic. If thrown away directly without treatment, it can harm aquatic life. To neutralize them, some base is added to such wastes.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

6. Short Answer Type Questions:

Question (i)
Name the source from which litmus solution is obtained. What is the use of this solution ?
Answer:
The solution of litmus is obtained from a plant called lichens found in nature. A strip of paper dipped in a solution of litmus is called litmus paper and the solution is called litmus solution. It is available as red and blue litmus.
Blue litmus turns red when dissolved in acidic solution and red litmus turns blue when dissolved in alkaline solution.

Question (ii)
Is the distilled water acidic/basic/neutral ? How would you verify it ?
Answer:
Distilled water is neutral. This is confirmed by the addition of litmus with which it gives green colour. The colour of Red litmus and blue litmus remain unchanged when added to distilled water showing that it is neutral in character.

Question (iii)
Describe the process of neutralisation with the help of an example.
Answer:
Neutralisation. The chemical reaction between an acid and an alkali is called neutralisation. As energy is released, salt and water are formed as products.
Acid + Alkali → Salt + Water + Heat (Energy)
Example : Hydrochloric Acid + Sodium Hydroxide → Sodium chloride + Water + Energy

Experiment: Fill a quarter of a test tube with dilute hydrochloric acid. Now add 2-3 drops of phenolphthalein solution (indicator) and note the color of the test tube solution. Now with the help of a dropper add a few drops of sodium hydroxide (alkali) in the test tube and gently shake the test tube. To the solution while stirring constantly, add Sodium hydroxide (alkali) solution till it turns light pink.
PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts 1
Now mix a drop of dilute Hydrochloric acid to it. You will notice that the color of the solution has disappeared (colourless) again. It is clear from this that phenolphthalein is pink in color as long as the solution is alkaline and the solution becomes colourless when the solution becomes acidic.

By mixing alkali solution with acid solution, they react with each other to neutralize the solution, i.e. the nature of acid and base gets cancelled out. This reaction is called Neutralisation.

Question (iv)
Name any two common acids and two common bases.
Answer:
Common acids. (1) Hydrochloric acid. (2) Sulphuric acid.
Common Bases. (1) Sodium hydroxide, (2) Calcium hydroxide

Question (v)
What are indicators ? Write their types and two examples of each.
Answer:
Indicators. Solution of substances that on reaction with acids, alkalis and neutral substances, give different colours, they are called indicators.
Types of indicators. There are two types of indicators:

  1. Natural indicators. These are indicators that are obtained from plants such as litmus, turmeric, China rose petals etc.
  2. Synthetic Indicators. These are indicators that are prepared in the laboratory, such as phenolphthalein and methyl orange etc.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

7. Long Answer Type Questions:

Question (i)
State differences between acids and bases.
Answer:
Differences between Acids and Bases :

Acids Bases
1. They are sour in taste.

2. They change the solution of blue litmus to red.

3. They don’t seem like soap when touched.

4. It doesn’t change colour of phenolphthalein solution.

5. They react with bases to produce salt, water and heat.

1. They are bitter in taste.

2. They change solution of red litmus to blue color.

3. They appear like soap when touched.

4. They react with phenolphthalein solution to make it pink.

5. They react with acid to produce salt, water and heat.

Question (ii)
Name the acid present in : (1) Vinegar (2) tamarind (3) citrus fruits and (4) curd.
Answer:
Substance The name of the acid

1. Vinegar  1. Acetic acid
2. Tamarind  2. Tartaric acid
3. Citric fruit  3. Citric acid
4. Spinach  4. Oxalic acid
5. Yogurt  5. Lactic acid

Question (iii)
You are given hydrochloric acid solution, sodium hydroxide solution and water in three different bottles. How would you check which bottle has which compound ?
Answer:
1. Take three test tubes. Take a few drops of the solution from each bottle separately in these three test tubes. Now add three drops of phenolphthalein solution to each of these test tubes. The test tube in which pink colour is observed contains base (Sodium Hydroxide) while the colour will not change in the other two test tubes.

2. Wash the test tubes and again take 5-5 drops of each solution in three different test tubes as before. Now put two drops of blue litmus in these test tubes. The test tube in which the blue litmus turns red contains acid (Hydrochloric acid).

3. Now we know that the third test tube contains water in which red and blue litmus don’t show any change.
In this way, we can find out which solution is present in which bottle.

PSEB Solutions for Class 7 Science Acids, Bases and Salts Important Questions and Answers

1. Fill in the Blanks:

(ii) is used to cure indigestion.
Answer:

(iii) Treatment of soil acidity is done by adding
Answer:
Lime

(iv) on reaction with a solution of phenolphthalein turn it pink.
Answer:
Alkali

(v) In the process of Neutralisation and are produced as a products.
Answer:
Salt, water

2. Match the Column A with Column B:

Column ‘A’ Column ‘B’
(i) Gooseberries (a) Acetic acid
(ii) Indigestion (b) Quick lime
(iii) Vinegar (c) Milk of Magnesia
(iv) Treatment of acidic soil (d) Ascorbic acid

Answer:

Column ‘A’ Column ‘B’
(i) Gooseberries (d) Ascorbic acid
(ii) Indigestion (c) Milk of Magnesia
(iii) Vinegar (a) Acetic acid
(iv) Treatment of acidic soil (b) Quick lime

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

3. Choose the Correct Answer:

Question (i)
Curd tastes sour so it is :
(a) basic
(b) acidic
(c) salt
(d) None of these.
Answer:
(b) acidic.

Question (ii)
Bases are :
(a) sour
(b) saltish
(c) bitter
(d) Neither sour nor sweet.
Ans.
(c) bitter.

Question (iii)
The acid present in vinegar is :
(a) Formic acid
(b) Citric acid
(c) Acetic acid
(d) Lactic acid.
Answer:
(c) Acetic acid.

Question (iv)
The acid present in curd is :
(a) Acetic acid
(b) Formic acid
(c) Citric acid
(d) Lactic acid.
Answer:
(d) Lactic acid.

(a) Calcium hydroxide
(b) turns blue litmus paper to red.
(c) Magnesium hydroxide
(a) Calcium hydroxide.

Acidic solution:
(a) turns red litmus paper to blue
(b) turns blue litmus paper to red
(c) neither turns blue litmus paper to red nor red litmus to blue
(d) None of these.

4. State True or False:

(i) Nitric acid turns red litmus blue.
Answer:
False

(ii) Sodium hydroxide turns blue litmus red.
Answer:
False

(iii) Sodium hydroxide and hydrochloric acid neutralize each other and form salt and water.
Answer:
True

(iv) Indicator is a substance which shows different colours in acidic and basic solution.
Answer:
True

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

(v) Tooth decay is caused by the presence of a base.
Answer:
False

Very Short Answer Type Questions

Question 1.
Name different types of substances based on their chemical nature.
Answer:

  1. Acidic
  2. Basic
  3. Neutral.

Question 2.
Name few substances that contain natural acids.
Answer:
Curd, lemon juice, orange juice, vinegar.

Question 3.
Name few substances which are basic in nature.
Answer:
Washing soda, baking soda.

Question 4.
Name the substance which is used to test the nature of chemical compounds.
Answer:
Indicator.

Question 5.
Name few natural indicators.
Answer:
Turmeric, litmus, China rose petals.

Question 6.
Which acid is present in curd ?
Answer:
Lactic acid.

Question 7.
What is household name of Acetic acid ?
Answer:
Vinegar.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

Question 8.
Amla is rich in which acid ?
Answer:
Ascorbic acid.

Question 9.
What is lime water ?
Answer:
It is calcium hydroxide, a base.

Question 10.
Name a base found in soaps.
Answer:
Sodium hydroxide.

Question 11.
What is use of Ammonium hydroxide ?
Answer:
For cleaning window glass panes.

Question 12.
What is source of litmus ?
Answer:
Lichens.

Question 13.
What are neutral substances ?
Answer:
Neutral Substances. The substances which do not change the colour of either blue or red litmus, are neutral substances.

Short Answer Type Questions

Question 1.
Write the properties of bases.
Answer:
Properties of Bases,

  1. Bases are bitter to taste.
  2. All alkalies have a slippery touch much like that of soap.
  3. Bases turn red litmus paper blue.
  4. Bases turn phenolphthalein solution from colourless to pink.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

Question 2.
Write the properties of acids.
Answer:
Properties of Acids.

  1. Acids turn blue litmus red.
  2. Acids contain hydrogen atom.
  3. Acids are sour in taste.
  4. Acids react with bases to form salt and water.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts 2

Question 3.
What is an indicator ? Name an indicator.
Answer:
Indicator. The chemicals or substances which give different colours with acids and bases, are known as acid-base indicators or simply indicators.
Phenolphthalein is another indicator which gives pink colour in alkaline solution and is colourless in acidic solution.

Question 4.
What is neutralization reaction ?
Answer:
Neutralization reaction. The process of treating an acid with an alkali/base to form a salt and water, is called neutralization reaction.
PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts 3

Question 5.
How the salts are formed?
Answer:
Salts. Salts are formed when an acid reacts with a base or salt is a compound which is formed by combination of acid with base.
PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts 4

Question 6.
Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar solution. How will you identify them ? You have only turmeric powder.
Answer:
Turmeric powder is a natural indicator. With turmeric powder, turmeric strips are prepared which give different colour in three given liquids.

Question 7.
Blue litmus paper when dipped in a solution remains blue. What is the nature of the solution ? Explain.
Answer:
Acids turn blue litmus red while bases do not change the colour of blue litmus. Therefore, the given solution is base as it has not changed the colour of blue litmus paper.

Question 8.
Explain why :
(i) An antacid tablet is taken when you suffer from acidity.
(ii) Calamine solution is applied on skin when an ant bites.
(ii) Factory waste is neutralized before disposing it into the water bodies.
Answer:
(i) An antacid tablet is taken when you suffer from acidity. To neutralize acidity, antacid tablet such as milk of magnesia is taken because it contains Magnesium hydroxide (base) which neutralizes the effect of acids.

(ii) Calamine solution is applied on skin when an ant bites. Ant bite contains formic acid which gets neutralized by calamine solution (zinc carbonate).

(iii) Factory waste is neutralized before disposing it into the water bodies. Factory waste usually contains acids, so they have to be neutralized as they can kill aquatic animals and plants. Some basic substances are used to neutralize such wastes.

Long Answer Type Question

Question 9.
What are the uses of neutralisation in our daily life ? Explain in detail.
Answer:
Uses of Neutralisation in daily life :
(i) As Antacids.
We know that in human stomach acid is produced called as stomach acids which contains hydrochloric acid which helps in digestion of food. But too much of it can cause indigestion, abdominal pain and heartburn, which is called acidity. To neutralize this excess acid, some mild alkali is used to relieve the pain. Such substances are called antacids, such as milk of magnesia (magnesium hydroxide), baking soda, etc.

(ii) As a treatment for insect stings.
Different species of insects such as; bees, wasps, spiders and ants etc. release formic acid in the body when they sting our body. The effect of formic acid can be reduced by neutralizing it with some mild alkali, such as baking soda or calamine solution.

(iii) As a treatment for soil acidity and alkalinity.
The presence of certain substances makes the soil more acidic or more alkaline. Excessive use of chemical fertilizers makes the soil acidic. Soil should be neutral for proper growth and development of plants. Soils are tested and if it is acidic, it is treated with lime (calcium oxide), Quick lime (Calcium hydroxide) etc. But if the soil is alkaline, it is mixed with organic matter which releases acid and neutralizes the alkali present in the soil.

(iv) As a treatment for factory wastes.
Industry and factory wastes are naturally acidic. If it is thrown away directly, it can affect and harm aquatic life. Therefore, it is important to neutralize the acid present in that waste. So some alkali is added to treat it.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

Acids, Bases and Salts PSEB 7th Class Science Notes

  • We eat many foods with different tastes in our daily life.
  • Some foods taste bitter, sour, sweet and salty.
  • The sour taste of the substance is due to the acid present in them.
  • The word acid is derived from the Latin word ‘acere’, which means sour.
  • Substances that have a bitter taste and are soapy to touch, they are called base.
  • Indicators are substances that give different colours to substances or solutions of acidic and basic nature. They are used to test the acidic or alkaline nature of substances.
  • Turmeric, litmus and China rose petals (Gudhal) are natural indicators.
  • Neutral solutions do not change the color of litmus red or blue because they are neither acidic nor basic.
  • Phenolphthalein is a synthetic indicator that is prepared in the laboratory.
  • Some acids are strong and some are weak.
  • The reaction between an acid and a base is called Neutralisation.
  • Antacids are used to treat indigestion.
  • Solution of baking soda (Sodium hydrogen carbonate) rubbed to treat the effects of insect bites.
  • The basicity of the soil is eliminated by the use of organic matter.
  • The acidity of soil is treated with bases like quick (calcium oxide) or slaked lime (Calcium hydroxide).
  • Waste products from factories should be released into the water only after treatment with basic substances.
  • Acids: Substances that have a sour taste and which react with blue litmus solution to make its color red are called acids.
  • Bases (Alkali): Substances that have a bitter taste and which react with red litmus solution to make it blue are called bases.
  • Neutralisation: The reaction between an acid and an alkali is called neutralisation.
  • Neutral solution: A solution which is neither acidic in nature nor alkaline in nature is called neutral solution or solution which does not change the color of the indicator is called neutral solution.
  • Indicators: Indicators are the substances which show different colours by reacting with different acids, salts and bases.

Punjab State Board PSEB 7th Class Science Book Solutions Chapter 5 Acids, Bases and Salts Textbook Exercise Questions and Answers.

PSEB 7th Class Science Solutions Chapter 4 Heat

PSEB Solutions for Class 7 Science Chapter 4 Heat

Science Guide for Class 7 PSEB Heat Intext Questions and Answers

Think and Answer (Textbook Page No. 37)

Question 1.
The normal temperature of our body is ……………… .
Answer:
The normal temperature of our body is 37°C.

Question 2.
The clinical thermometer can measure temperature above 45°C. (T/F)
Answer:
False.

PSEB 7th Class Science Solutions Chapter 4 Heat

Think and Answer (Textbook Page No. 39)

Question 1.
Thermometer should be held from its bulb.(T/F)
Answer:
False.

Question 2.
The thermometer should not touch the ………………. of the beaker.
Answer:
The thermometer should not touch the bottom or sides of the beaker.

Think and Answer (Textbook Page No. 40)

Question 1.
The handle of cooking vessels are good conductor of heat. (True/False)
Answer:
False.

Question 2.
The handle of electric iron is good conductor of heat. (True/False)
Answer:
False.

Think and Answer (Textbook Page No. 42)

Question 1.
The ventilators in the rooms are used to expell cold air. (True/False)
Answer:
False.

Question 2.
The liquids are always heated from the bottom. (True/False)
Answer:
True.

Think and Answer (Textbook Page No. 44)

Question 1.
We wear light coloured clothes in winter. (True/False)
Answer:
False.

Question 2.
Dark coloured clothes absorbs less heat. (True/False)
Answer:
False.

PSEB 7th Class Science Solutions Chapter 4 Heat

PSEB 7th Class Science Guide Heat Textbook Questions and Answers

1. Fill in the blanks:

(i) The hotness of an object is a measured by its …………………….
Answer:
Temperature

(ii) The mode of heat transfer without any medium is called ………………….. .
Answer:
Radiation

(iii) Air is ………………….. conductor of heat.
Answer:
bad

(iv) The normal temperature of the human body is ……………………. °C.
Answer:
37°C

2. Write True or False:

(i) Metals are insulators of heat.
Answer:
False

(ii) Sea breeze arises due to conduction.
Answer:
False

(iii) We get heat from the sun by radiation.
Answer:
True

(iv) Wool is good conductor of heat.
Answer:
False

PSEB 7th Class Science Solutions Chapter 4 Heat

(v) Range of clinical thermometer is 35° C to 42°C.
Answer:
False

3. Match the Column ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
1. Land breeze blows during

2. Sea breeze blows during

3. We prefer light coloured clothes in

4. We prefer dark coloured clothes in

(a) winter

(b) night

(c) daytime

(d) summer

Answer:

Column ‘A’ Column ‘B’
1. Land breeze blows during

2. Sea breeze blows during

3. We prefer light coloured clothes in

4. We prefer dark coloured clothes in

(c) daytime

(b) night

(d) summer

(a) winter

4. Choose the Correct Answer:

Question (i)
Temperature of human body is:
(a) 100°C
(b) 0°C
(c) 37° C
(d) 98°C.
Answer:
(c) 37° C.

Question (ii)
Which is bad conductor of heat ?
(a) Aluminium
(b) Iron
(c) Copper
(d) Wood.
Answer:
(d) Wood.

Question (iii)
One litre of water at 30°C is mixed with one litre of water at 50°C. Then temperature of mixture will be :
(a) 80°C
(b) More than 50°C but less than 80°C’
(c) 20°C
(d) Between 30°C and 50°C
Answer:
(d) Between 30°C and 50°C.

Question (iv)
A wooden spoon is dipped in a cup of ice cream. Its other end:
(a) becomes cold by the process of conduction.
(b) becomes cold by the process of convection.
(c) becomes cold by the process of radiation.
(d) does not become cold.
Answer:
(d) does not become cold.

Question (v)
Land breeze is:
(a) cool air from land to sea
(b) cool air from sea to land
(c) hot air from land to sea
(d) hot air from sea to land.
Answer:
(a) cool air from land to sea.

Short Answer Type Questions

Question (i)
State the condition which determine the direction of flow of heat.
Answer:
When two objects are in contact with each other, the heat is transmitted from the object at higher temperature to the object at a lower temperature.

PSEB 7th Class Science Solutions Chapter 4 Heat

Question (ii)
What is clinical thermometer ? Write its range.
Answer:
Clinical thermometer. Clinical thermometer is a device by which a human body temperature is measured. It is also called Medical thermometer’s range in from 35°C to 42°C.

Question (iii)
What is the use of kink in a clinical thermometer ?
Answer:
Medical thermometer has a kink (bend) just above the bulb, the function of which is to prevent the mercury level from falling because of its weight. If kink is not present there then the mercury level will drop so that the human temperature will not be measured accurately.

Question (iv)
What is Lab thermometer ? Write its range.
Answer:
Lab Thermometer. An instrument used to measure the temperature of objects other than human beings (or living things) is called Lab thermometer. The range of lab thermometer is usually 10°C to 110°C.

Question (v)
Why do we prefer dark clothes in winters and light one in summers ?
Answer:
Darker fabrics absorb more heat than light coloured fabrics. So in winter we wear dark coloured clothes to keep our body warm by absorbing more heat, whereas light coloured clothes absorb lesser amount of heat and are also good reflector so our body does not get much heat.

Question (vi)
Why do we wear woollen clothes in winters ?
Answer:
Air is trapped in the wool fibres. Since air is a bad conductor of heat, so it does not allow heat to be transmitted to the cold environment outside. That is why we feel warm in winter by wearing woollen clothes.

6. Long Answer Type Questions:

Question (i)
What are the various modes of heat transfer ? Explain.
Answer:
There are three modes of heat transfer :
1. conduction.
2. convection,
3. radiation.

1. Conduction.
It is that method of heat transfer in which heat is transmitted from the hotter end to the colder end of the object without the actual movement of the heated partilces. Solids are heated by this method.

2. Convection.
It is the process of heat transfer due to the actual movement of the heated particles of liquid or gas. Liquids and gases are heated by this method.

3. Radiation.
It is the process in which heat is transmitted directly from the ource of heat or hot object to a cold object without medium in between them. In other words no medium is required for heat radiation

PSEB 7th Class Science Solutions Chapter 4 Heat

Question (ii)
Explain the formation of sea breeze and land breeze in coastal areas ?
Answer:
Sea breeze.
During day time the ground is heated by the heat of the sun, which causes the ground air to heat up, roll and rise. Cold air from the ocean begins to rush towards the ground to take it’s place. The warm air from the land moves towards the sea to complete the cycle. The wind that blows from the ocean to the land is called the sea breeze.
PSEB 7th Class Science Solutions Chapter 4 Heat 1
Land breeze.
Due to higher heat absorption capacity the water cools down more slowly than the land, so cool air from the land starts rushing from the land towards the sea at night. This is called land breeze.
PSEB 7th Class Science Solutions Chapter 4 Heat 2

PSEB Solutions for Class 7 Science Heat Important Questions and Answers

1. Fill in the blanks:

(i) The degree of hotness of an object is determined by its …………………
Answer:
temperature

(ii) Temperature of boiling water cannot be measured by a ………………. thermometer.
Answer:
clinical

(iii) Temperature is measured in degree ……………… .
Answer:
Celsius

(iv) A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by
the process of ………………..
Answer:
conduction

(v) Clothes of …………………. colours absorb more heat than light coloured clothes.
Answer:
dark

2. Match the Column ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
(i) Medical thermometer

(ii) Black coloured objects

(iii) Woollen clothes

(iv) Transfer of heat

(v) Light coloured clothes

(a) From high temperature to low temperature

(b) In winter

(c) In summer

(d) Better absorbent and radiator

(e) To measure the temperature of human beings.

Answer:

Column ‘A’ Column ‘B’
(i) Medical thermometer

(ii) Black coloured objects

(iii) Woollen clothes

(iv) Transfer of heat

(v) Light coloured clothes

(e) To measure the temperature of human beings

(d) Better absorbent and radiator

(b) In winter

(a) From high temperature to low temperature

(c) In summer

3. Choose the Correct Answer:

Question (i)
We can measure temperature with clinical thermometer
(a) From 30°C to 42°C
(b) From 35°C to 42°C
(c) From 35°C to 45°C
(d) None of these.
Answer:
(b) From 35°C to 42°C.

PSEB 7th Class Science Solutions Chapter 4 Heat

Question (ii)
The reliable measure of heat of an object is :
(a) The heat of that object
(b) The degree of hotness or coldness of that object
(c) The physical touch
(d) None of the above.
Answer:
(b) The degree of hotness or coldness of that object.

Question (iii)
The range of laboratory thermometer is :
(a) -10°C to 100°C
(b) 35°C to 42°C
(c) -10°C to 110°C
(d) 94°F to 108°F.
Answer:
(c) ~10°C to 110°C.

Question (iv)
Heat from sun reaches us by the process of :
(a) conduction
(b) convection
(c) radiation
(d) None of the above.
Answer:
(c) radiation.

Question (v)
Heat is transferred in liquids and gases by :
(a) conduction
(b) radiation
(c) convection
(d) None of the above.
Answer:
(c) convection.

Question (vi)
Clinical thermometer is filled with :
(a) Water
(b) Lead
(c) Mercury
(d) Air.
Answer:
(c) Mercury.

Question (vii)
What kind of clothes do we wear in summer ?
(a) Cotton
(b) Silky
(d) Wool.
(c) Jute
Answer:
(a) Cotton.

4. State True or False:

(i) We wear both light and dark clothes in summer.
Answer:
False

PSEB 7th Class Science Solutions Chapter 4 Heat

(ii) In coastal areas, the wind blowing from the sea towards the coast at night is called land breeze.
Answer:
False

(iii) Woollen garments provide warmth in winter as wool fibres traps in air.
Answer:
True

(iv) Heat transfer between liquids and gases is by convection method.
Answer:
True

(v) The thermometer should be washed with lukewarm water before use to measure temperature.
Answer:
False

Very Short Answer Type Questions

Question 1.
What is temperature ?
Answer:
Temperature. The degree of hotness or coolness of an object is its temperature.

Question 2.
What is thermometer ?
Answer:
Thermometer. It is a device used to measure the temperature of an object.

Question 3.
Name two types of thermometers.
Answer:

  1. Clinical thermometer and
  2. Laboratory thermometer.

PSEB 7th Class Science Solutions Chapter 4 Heat

Question 4.
Which metal is used in thermometers ?
Answer:
Mercury (Hg).

Question 5.
Which scales are used to measure temperatures ?
Answer:
Two scales are mainly used which are (i) Celsius scale and (ii) Fahemheit scale.

Question 6.
What is range of clinical thermometer ?
Answer:
35°C to 42°C.

Question 7.
Why is a thermometer jerked before taking temperature of a person ?
Answer:
To bring the mercury level below 35°C.

Question 8.
What is normal body temperature of healthy person ?
Answer:
37°C.

Question 9.
Name the thermometer used for noting weather temperature.
Answer:
Maximum-Minimum thermometer.

Question 10.
What is range of laboratory thermometer ?
Answer:
-10°C to 110°C.

PSEB 7th Class Science Solutions Chapter 4 Heat

Question 11.
Which solution is used to wash thermometer before and after use ?
Answer:
Antiseptic solution.

Question 12.
How are laboratory thermometers read ?
Answer:
In vertically upright position.

Short Answer Type Questions

Question 1.
When cold milk is added to hot tea, how does the heat transfer take place ?
Answer:
When cold milk is added to hot tea. the two come in contact with each other. The transfer of heat energy takes place from hot molecules of tea to cold molecules of milk by the process called convection.

Question 2.
What are the main conditions necessary for the flow of heat ?
Answer:
Conditions for the flow of heat. The following are three conditions responsible for the flow of heat from one place to another or from one body to another body :

  1. The two substances should be in contact with each other.
  2. The temperature of both the substances should be different.
  3. The heat flows from hot to cooler substance.

Question 3.
If a spoon is held over fire, it becomes hot after sometime. Describe the process of heating up.
Answer:
We know that in a solid the molecules are packed close together. When one end of the spoon is held over the fire, the molecules of material of spoon absorb the heat energy and begin to vibrate rapidly. These molecules handover heat energy to the neighbouring molecules, in turn, cause their neighbouring molecules to vibrate. This process continues along the length of the spoon and energy is transferred from the hotter part to the colder part. After sometime, the other end of the spoon also becomes hot.

Question 4.
Why is it preferred to wear bright clothes in summer and dark clothes in winter ?
Answer:
Dark coloured clothes are good absorbers of heat as compared to white clothes. The dark coloured clothes absorb the heat falling on them and become wanner. So we feel warm in winter by wearing these clothes. On the other hand, white clothes reflect heat coming from the sun. That is why, we prefer to wear bright clothes in summer and dark clothes in winter.

Question 5.
Define conduction. Why the handles of cooking utensils are made of insulators ?
Answer:
Conduction. The mode of transfer of heat in which heat is transferred from one particle to another without the actual motion of the particles, is called conduction.
The handles of cooking utensils are made up of insulating materials because they do not allow heat to flow through them. So heat cannot reach our body and thus our hand is prevented from burning.

Question 6.
Define radiation.
Answer:
Radiation. The process of transfer of heat from one body to another without heating the intervening medium, is called radiation. No medium is needed for the transference of heat by this process.

PSEB 7th Class Science Solutions Chapter 4 Heat

Question 7.
Distinguish between heat and temperature.
Answer:
Differences between heat and temperature.
TABLE

Question 8.
What is convection ? Give two practical applications of convection of heat.
Answer:
Convection.
The process of transference of heat in which heated gas or a liquid particles actually move from one place to another, is called convection. All the liquids and gases are heated by the method of convection.

Practical applications :

  • When a stove is lighted, the air in contact with the hot stove becomes warm. On being heated, it expands and becomes lighter. As a result, it rises upwards and the cool air from its surrounding comes to take its place.
  • The ventilation of ordinary buildings is due to convection.

Question 9.
As soon as the tube is removed from the source of heat, the level of liquid drops. How is this avoided in the thermometer that doctors use ?
Answer:
It is seen that the level of liquid fails in a narrow-tube (capillary tube) when it is removed from the source of heat. But when the doctor’s thermometer is removed from the source of heat, the level of mercury does not fall by itself. It is because a kink is provided in the tube of clinical thermometer which prevents mercury from falling down due to its own weight.

Question 10.
Discuss why wearing more layers of clothing during winter keeps us warm than wearing just one thick piece of clothing.
Answer:
Different layers of clothing trap air inside them. Air is a poor conductor of heat so it prevents the flow of heat from our body to the cold surrounding and keeps us warm.

Long Answer Type Questions

Question 1.
Give an experiment to show that black bodies are good absorbers and good raidators.
Answer:
Experiment. Take two tin cans of the same size. Paint one of them black and other white from outside. Pour equal amount of water in each can. Now place them in the sun for about an hour. When we touch water in the tin cans we find that the water in the black tin has become warmer than that in the other tin. Since the size of the tins is the same, this shows that black body has absorbed more heat radiations than the other one.
PSEB 7th Class Science Solutions Chapter 4 Heat 3
You can also do the reverse experiment by taking equal amount of hot water in each can. Leave the cans in a shady place for 10 minutes and record the temperature of each can. You would find the water in the dark had cooled down more. Thus, we conclude that black bodies are good absorbers and also good radiators of heat.

Question 2.
Give an experiment to show the transfer of heat by conduction.
Answer:
Experiment. Take a flat aluminium rod. Fix some iron nails on this rod with the help of molten wax. Clamp this rod in a stand as shown in the figure.
Heat one end of the rod with the help of spirit lamp. The iron nails drop one by one, starting from the hot end. It shows that heat is transferred slowly from one end of the rod to the other end by conduction.
PSEB 7th Class Science Solutions Chapter 4 Heat 4
Conduction of heat takes place from hot part of the object to its colder parts; or from one hot object to a colder object, happens only if:

  1. the two parts are in contact, and
  2. their temperatures are different.

PSEB 7th Class Science Solutions Chapter 4 Heat

Heat PSEB 7th Class Science Notes

  • The method of determining whether an object is hot or cold by touching it is not reliable.
  • Temperature is the degree of hotness or coldness of an object.
  • The hot or cold state of an object, i.e. the temperature is measured with an instrument called thermometer.
  • The temperature of a human or living organism is measured with a medical thermometer(or clinical thermometer)
  • A scale is present on a medical thermometer. This scale is either in Celsius [°C] or Fahrenheit [°F] or both.
  • Medical thermometers have a narrow, homogeneous tube of glass with a bulb at the bottom.
  • There is a kink near the bulb of a medical thermometer that prevents the mercury level from falling as a result of its weight.
  • Should clean with antiseptic solution before and after use of medical thermometer.
  • The scale range of medical thermometers is from 35°C to 42°C.
  • Before using a medical thermometer, make sure that the mercury level is below 35° C. If not, hold the thermometer firmly and shake it to bring level of mercury below 35°C.
  • The normal temperature of a healthy person is 37°C or 98.4°F.
  • There are other thermometers to measure the temperature of objects. One of these is the Lab thermometer. Lab thermometer ranges from -10°C to 110° C.
  • The temperature of the object should be measured with a lab thermometer when the | mercury level in the thermometer becomes stable.
  • The method by which heat is transferred from the hotter end of an object to the cold end by the particles of material of the object, is called conduction. Solids are heated by conduction method.
  • Materials that transmit heat are called conductors,
  • Items made of iron, silver, copper, aluminium are heat conductors.
  • Substances that do not conduct heat well are called insulators or non-conductors, e.g. Wood, plastic and rubber.
  • Air is not a good conductor of heat.
  • The method of heat transfer in which heat is transmitted by the motion of hot molecules of a substance is called convection.
  • Heat is transmitted in liquids and gases by the convection method,
  • In coastal areas, the wind that blows from the sea to the coast during the day is called Sea breeze.
  • In coastal areas, the air that blows from the coast to the sea at night is called land breeze.
  • Radiation is the method of transfer of heat due to the emission of radiations by hot objects without a medium.
  • Dark coloured fabrics absorb heat more than light coloured fabrics. So in winter we wear dark colours and in summer we wear light coloured clothes.
  • Woollen garments keep us warm in winter because of the air trapped in the wool fibres which is a bad conductor of heat.
  • Heat: It is an agent which produces in us the sensation of warmth. This is a kind of energy.
  • Temperature: Degree of hotness or coldness measured on a definite scale.
  • Thermometer: An instrument used to measure the temperature of an object.
  • Celsius Scale: The Celsius scale is a scale for measuring temperature. Sometimes it is also called as centigrade scale.
  • Resistor: A substance through which heat cannot be transmitted properly is considered to be resistor or resistant to heat.
  • Conduction: This is the method of heat transfer in which heat passes from the hot end of the object to the cold end through the molecules of the material, but the molecules of the object remain fixed in their place.
  • Convection(Liquid or Gas): This is the method of heat transfer in which heat is transferred from the source of heat to the cold part due to the motion of hot molecules and the cold molecules come down to take their place. This method is used for heating liquids and gases.
  • Radiation: This is the method of heat transfer in which heat is transmitted from a hot source or body directly to a cool body without affecting the medium.
  • Sea breeze: Due to the heat of the sun during the day, the soil of the land gets heated very quickly when water molecules of ocean are not so hot. Therefore, the air near the ground gets warmer and rises up due to being lighter. To replace it, cool air begins to flow from the ocean, causing air currents to flow. The wind that blows from the ocean to the land is called sea breeze.
  • Land breeze: Due to high heat absorption capacity, water cools later than land, due to which cold air starts flowing towards seawater which is called land breeze.
  • Fahrenheit Scale: The Fahrenheit scale is a scale designed to measure temperature.

Punjab State Board PSEB 7th Class Science Book Solutions Chapter 4 Heat Textbook Exercise Questions and Answers.

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

PSEB Solutions for Class 7 Science Chapter 3 Fibre to Fabric

Science Guide for Class 7 PSEB Fibre to Fabric Intext Questions and Answers

Think and Answer (Textbook Page No. 24)

Question 1.
Name any two natural fibres obtained from plants.
Answer:
Natural Fibres obtained from Plants : (1) Cotton, (2) Bamboo.

Question 2.
Name any two natural fibres obtained from animals.
Answer:
Natural fibres obtained from animals : (1) wool, (2) silk.

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

Question 3.
Name any three animals which provide us wool.
Answer:
Animals that provide wool : (1) sheep, (2) yak, (3) goat.

Question 4.
Why do some animals have a thick coat of hairs ?
Answer:
The hair of some animals is dense because the wool-giving sheep that are found in cold regions have a dense coat of hair over their body, so that they can keep their body warm in winter. Hair traps a lot of air. This air is a poor conductor of heat and prevents the body heat to escape to the surrounding environment and thus keeps the sheep warm.

Think and Answer (Textbook Page No. 29)

Question 1.
What difference in smell you notice on burning silk thread, thread and wool ?
Answer:
The process of burning of silk gives a smell like burning of meat. When cotton thread bums, it gives smell like burning of paper but the burning of wool gives strong smell like burning of hair.

Question 2.
What type of ash is formed in the above activity ?
Answer:
The ash left after burning of cotton thread is of grey colour. The burning of silk thread and woollen thread produces ash like hollow bead of black colour.

Question 3.
Does the smell of burning of silk thread is same as the smell of burning woollen thread ?
Answer:
No. The smell of burning of silk thread is just like burning of hair while the smell of burning of wool thread is like cooking meat.

PSEB 7th Class Science Guide Fibre to Fabric Textbook Questions and Answers

1. Fill in the Blanks:

(i) Wool is obtained from the …………….. of sheep, goat and yak.
Answer:
hairs

(ii) Long hair on the body protect animals from ………………
Answer:
cold

(iii) Removal of fleece from the skin of animal is called ………………
Answer:
shearing

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

(iv) Rearing of silkworm is called ………………….
Answer:
sericulture

(v) The process of unwinding the filaments from the boiled cocoons, is called ………….. .
Answer:
reeling

2. Match the Column ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
1. Scouring

2. Sericulture

3. Protein

4. Mulberry leaves

5. Lohi

(a) Food of silkworm

(b) Sheeps found in Rajasthan and Punjab

(c) Silk fibre made up of

(d) Rearing of silkworms

(e) Cleaning sheared fleece

Answer:

Column ‘A’ Column ‘B’
1. Scouring

2. Sericulture

3. Protein

4. Mulberry leaves

5. Lohi

(e) Cleaning sheared fleece

(d) Rearing of silkworms

(c) Silk fibre made up of

(a) Food of silkworm

(b) Sheep found in Rajasthan and Punjab

3. Choose the Correct Answer:

Question (i)
The fibre which is not produced by animals:
(a) Angora Wool
(b) Wool
(c) Jute
(d) Silk
Answer:
(c) Jute.

Question (ii)
Wool is commonly obtained from:
(a) Sheep
(b) Goat
(c) Yak
(d) All of the above
Answer:
(a) Sheep.

Question (iii)
Washing of sheared hair is called:
(a) Scouring
(b) Sorting
(c) Shearing
(d) Dyeing
Answer:
(a) Scouring.

Question (iv)
Wool is chemically:
(a) Fat
(b) Protein
(c) Carbohydrate
(d) None of these
Answer:
(a) Fat.

Question (v)
The animal that does not yield wool is:
(a) Alpaca
(b) Woolly dog
(c) Camel
(d) Goat
Answer:
(b) Woolly dog.

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

4. Write True or False:

(i) Air is a bad conductor of heat.
Answer:
True

(ii) Air trapped in long hair does not allow body heat to escape from body.
Answer:
True

(iii) In Tibet and Ladakh, wool is obtained from yak.
Answer:
False

(iv) Rearing of silk moths is called apiculture.
Answer:
True

(v) The cover around the body of caterpillar is called cocoon.
Answer:
False

(vi) Tassar silk and moonga silk are produced by silk moth who have been feeding on non-mulberry trees.
Answer:
False

5. Very Short Answer Type Questions:

Question (i)
Names any two plant fibres and animal fibres.
Answer:
Fibres obtained from plants : (1) Husk fibre, (2) Cotton.
Fibres obtained from animals : (1) Wool, (2) Silk.

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

Question (ii)
What is sericulture ?
Answer:
Sericulture. Cultivation of silkworms to obtain silk is called sericulture.

Question (iii)
Name the common animals who yield fleece.
Answer:
(1) Yak, (2) Sheep, (3) Camel (4) Goat

6. Short Answer Type Questions:

Question (i)
What do you understand by Angora and Kashmere wool ?
Answer:
North Angora wool. It is obtained from goats found in mountainous places like Jammu and Kashmir.
Kashmere Wool. Kashmere wool is woven into pashmina shawls.

Question (ii)
Write the states where the following breeds of sheep are found : Lohi, Bakharwal, Nali and Marwari.
Answer:

Types of Sheep State where they are found
Lohi Punjab, Rajasthan
Bakharwal Jammu, Kashmir
Nali Punjab, Haryana, Rajasthan
Marwari Gujarat

Question (iii)
Write all the steps involved in processing fibres into wool.
Answer:
The Different Stages of Rise to the North

  1. Shearing or cutting
  2. Scouring
  3. Sorting
  4. Combing
  5. Dyeing
  6. Spinning or weaving.

Question (iv)
Why do some animals have a thick coat of hair ?
Answer:
The hair of some animals is dense because the wool-giving sheep that are found in cold regions have a dense coat of hair over their body, so that they can keep their body warm in winter.
Hair traps a lot of air. This air is a poor conductor of heat and prevents the body heat from circulating in the external environment which keeps the sheep warm.

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

Question (v)
How is silkmoth reared ?
Answer:
Rearing of Silkworm. The female silkworm lays hundreds of eggs at a time. These eggs are carefully collected on cloth strips or paper and kept in healthy conditions, at suitable heat and humidity conditions. The eggs are kept warm to a suitable temperature to allow the larvae to hatch. The larvae, called caterpillars or silkworms, are housed on mulberry leaves.

They eat these leaves day and night and increase in size considerably. Then these are kept in clean bamboo trays with fresh mulberry leaves. After 25-30 days, they stop eating and the caterpillars are moved to bamboo chambers to make cocoons. So the twigs are placed in a tray, with which the cocoons clrng. Caterpillar or silkworms form cocoons in which silkworm develop.

7. Long Answer Type Questions:

Question (i)
Write all the steps in processing silk from cocoons.
Answer:
The process of making silk from the cocoon. The cocoon has a continuous growth of insect inside it. Silk thread is obtained from the cocoon of the silkworm. Silk threads are used to make silk fabrics. These soft silk threads can be as strong as steel wires. There are many types of silkworms that look different from each other.

The different textures (rough, soft, shiny etc.) of silks like tusser silk, mooga silk, consa silk etc. are obtained from different types of insect cocoons. The most common silkworm is the mulberry silkworm. The silk obtained from this worm is very soft, shiny and flexible. It can be painted in beautiful colours. Sericulture or rearing of silkworms is a very old occupation in India. India produces a lot of silk commercially.

Question (ii)
Draw a labeled diagram and explain the life cycle silkmoth.
Answer:
PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric 1
Life Cycle of Silkmoth. The life cycle of the silkworm is summarized in the following steps:
Step 1. The female silkworm lays eggs on the leaves of mulberry.

Step 2. The eggs give birth to larvae that take on an insect-like structure over the next two weeks called a caterpillar or silkworm.

PSEB Solutions for Class 7 Science Fibre to Fabric Important Questions and Answers

1. Fill in the Blanks:

(i) The wool is obtained from the …………….. of sheep, goat and yak.
Answer:
skin

(ii) Long hair on the body of animals protect them from ……………… .
Answer:
cold

(iii) The process of yielding wool from the skin of animal is known as ………………….. .
Answer:
shearing

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

(iv) Rearing silk worm is called ………………. .
Answer:
sericulture

(v) The process of removing threads from the boiled cocoon is called ………………….. .
Answer:
reeling.

2. Match the Column I with Column II:

Column I Column II
1. Scouring

2. Mulberry leaves

3. Yak Cocoon

(a)  Yields silk fibres

(b)  Wool yielding animal

(c)  Food of silk worm.

(d)  Reeling

(e)  Cleaning sheared skin.

Answer:

Column I Column II
1. Scouring

2. Mulberry leaves

3. Yak

4. Cocoon

(e) Cleaning sheared skin.

(c) Food of silk worm.

(b) Wool yielding animal

(a) Yields silk fibres.

3. Choose the Correct Answer:

Question (i)
We get from yak:
(a) silk
(b) cotton
(c) wool
(d) None of these.
Answer:
(c) wool.

Question (ii)
For making Pashmina shawls, wool is obtained from:
(a) Yak
(b) Camel
(c) Sheep
(d) Angora goat.
Answer:
(d) Angora goat.

Question (iii)
In South America wool is obtained:
(a) Llama and Angora goat
(b) Llama and yak
(c) Sheep and Llama
(d) Llama and Alpaca.
Answer:
(d) Llama and Alpaca.

Question (iv)
Bakharwal breed of sheep is found:
(a) In Punjab
(b) In Rajasthan
(c) In Haryana
(d) In Jammu and Kashmir.
Answer:
(d) In Jammu and Kashmir.

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

Question (v)
The sheep’s hair are mostly cut in:
(a) Summer
(b) Winter
(c) Both Summer & Winter
(d) Neither very hot or cold season.
Answer:
(a) Summer.

Question (vi)
Process of taking out silk yarn from cocoons:
(a) Rearing silk worms
(b) Sericulture
(c) Reeling
(d) None of these.
Answer:
(c) Reeling.

Question (vii)
Lohi breed of sheep is found in:
(a) Punjab and Rajasthan
(b) Punjab and Himachal
(c) Punjab and Gujarat
(d) Punjab and Jammu.
Answer:
(a) Punjab and Rajasthan.

4. State True or False:

(i) Pashmina Shawl is made from llama and alpaca wool.
Answer:
True

(ii) Wool is chemically a carbohydrate.
Answer:
False

(iii) Warm silk is obtained from leaf-eating insects.
Answer:
True

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

(iv) The wool obtained from the Marwari sheep (breed of Gujarat) is very soft.
Answer:
False

Very Short Answer Type Questions

Question 1.
How do hair help animals to keep them warm ?
Answer:
Hair trap a lot of air. As air is bad conductor of heat so it does not allow heat of the body to go to the surroundings and therefore, keeps the animal warm.

Question 2.
From where wool is derived ?
Answer:
Hairy skin of animals.

Question 3.
Name wool yielding animals.
Answer:
Yak, Sheep, Goat, Lama, Alpaca.

Question 4.
What is pashmina ?
Answer:
Pashmina is soft wool obtained from Kashmiri goat.

Question 5.
In which part of India is Yak wool commonly seen ?
Answer:
Tibet and Ladakh.

Question 6.
Which animal is commonly reared for wool ?
Answer:
Sheep.

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

Question 7.
What is called woollen thread ?
Answer:
Fiber.

Question 8.
In winter, which food is given to sheep ?
Answer:
Leaves, grains, dry fodder.

Question 9.
Which instrument is used for shearing ?
Answer:
Machine similar to those used by barbers.

Question 10.
In which season, fleece is sheared off ?
Answer:
Summer or hot season.

Question 11.
Name some Indian breed of sheep.
Answer:
Lohi, Rampur bushair, Nali, Marwari, Bakharwal, Patanwad.

Short Answer Type Questions

Question 1.
Write down the different steps for obtaining wool from sheep.
Answer:
Steps for obtaining wool
Shearing, scouring, sorting, drying, dyeing, spinning and weaving.

Question 2.
In which part of India, sheep are reared for wool ?
Answer:
Hills in Kashmir, Himachal, Uttranchal, Arunachal, Sikkim and plains of Haryana. Punjab, Rajasthan and Gujrat.

Question 3.
Why does shearing not hurt the sheep ?
Answer:
Hair grow on uppermost layer of the skin, which consists of dead cells. So sheep do not feel pain of the time of shearing.

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

Question 4.
Why is fleece scoured ?
Answer:
Fleece is scoured to remove dirt, grease and dust from it. This process is known as scouring

Question 5.
What happens when silk fibre and artificial silk thread is burned ?
Answer:
Burning of silk fibres produces no smell and no residue is left behind.
While burning of artificial silk thread produces pungent smell and a fluffy residue formed.

Long Answer Type Questions

Question 1.
Write in brief the process of obtaining silk ?
Answer:
Silk is obtained from silk moth which are reared and their cocoons are collected to get silk fibre. The process involves two steps:
(i) Rearing silk worms.
(ii) Processing silk.

(i) Rearing silk worms. The eggs layed by female silk moth are stored carefully on strips of cloth or paper and kept under hygienic conditions and suitable temperature and humidity.
PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric 2
Sometimes eggs are warmed to hatch larvae and these larvae are fed on fresh leaves of mulberry tree. These larvae called caterpillars or silkworms eat day and night to grow into enormous sizes.

These larvae are kept in clean bamboo trays along with freshly chopped mulberry leaves. After 20 to 25 days, the caterpillass or silkworms stop eating and move to a tiny chamber of bamboo tray to spin cocoons. Inside cocoon, develops the silk moth.

(ii) Processing silk. A pile of cocoons are collected and kept under sun. or boiled or exposed to steam to separate out the silk fibres. These silk fibres are reeled and then spun into silk threads which are woven to give silk cloth.

Question 2.
Describe in brief the steps involved in obtaining wool from sheep.
Answer:
Processing of silk involves following steps :
(i) Boiling. First cocoons are first boiled in hot water then treated in ovens to kill larvae inside. If in case larvae an not killed, they are allowed to grow. They will break the cocoon and thereby reducing the length of the silk fibre. The hot water soften the silk gum to unwinding of silk fibre as one continuous thread.

(ii) Reeling. It is the process of taking out the thread from the cocoon. Reeling is done with the help of special machines.

(iii) Throwing. In this step raw silk is twisted to produce thrown silk. It prevent the silk from splittings into individual fibres.

(iv) Deying. Thrown silk is then dyed for making coloured fabrics. Dyed Silk fibres are spun into silk threads, which are waven into silk clothes.

PSEB 7th Class Science Solutions Chapter 3 Fibre to Fabric

Fibre to Fabric PSEB 7th Class Science Notes

  • Fibre of wool and silk are derived from animals in nature.
  • The fibre of wool is obtained from sheep, goats or yaks.
  • The thin skin of a sheep has two types of fibres :
    (1) Coarse beard hair and (2) Fine soft hair under hair close to skin.
  • Some breeds of sheep possess only fine under hair, their parents are specially chosen to give birth to sheep which have only soft under hair, such selection of parents for specific character is called ‘selective breeding’.
  • There are different types of wool, such as sheep’s wool, Angoora and cashmere wool.
  • Sheep are reared to obtain wool.
  • Sorters disease is spread by the bacterium Anthrax.
  • Raising silkworms to get silk is called Sericulture.
  • Female silkworms lay hundreds of eggs.
  • The larvae that hatch out from eggs are called caterpillars.
  • Caterpillars grow size and become pupae (adult).
  • Then pupa swings it’s head from side to side in the form of figure of eight(8). During this movement caterpillar secret fibre made up of a protein which hardens on exposure to air and become silk fibre.
  • Caterpillar also covers itself completely with these silk fibres and this covering is known as Cocoon.
  • The most common silk moth is mulberry silk moth. Other types of silk are Tassar silk, Mooga silk and Kosa silk etc.
  • The process by which cocoons are boiled or given steam to extract silk fibres, is called Reeling of silk.
  • Reeling is done with special machines.
  • Silk thread is used to weave silk fabric.
  • Some Important Definitions !
  • Tuft: A cluster of sheep’s body hair.
  • Reeling: The process of extracting silk fibres by boiling or steaming silk cocoons.
  • Scouring: The sheared skin with hair is washed thoroughly to remove grease, dust, and sweat, is called scouring.
  • Cocoon: A layer of silk fibres that covers the caterpillar is called cocoon.
  • Sericulture (rearing silkworms): Rearing of silkworms to get silk, is called Sericulture.
  • Shearing or shaving: The process of removing a thin layer of sheep’s hair and skin from a sheep’s body is called shearing.
  • Throwing: Raw silk is spun to make raw silk stronger (thick). This process is called throwing. This protects the fibres from breaking down.
  • Combing: The process of removing small swollen fibres called burrs is called combing.
  • Dyeing or colouring: Sheep wool can be dyed in different colours as the natural color is only black, brown or white.
  • Selective Breeding: Two sheep with special required traits are selected as parents for breeding and reproducing a sheep of required traits. This process is said selective reproduction.

Punjab State Board PSEB 7th Class Science Book Solutions Chapter 3 Fibre to Fabric Textbook Exercise Questions and Answers.

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

PSEB Solutions for Class 7 Science Chapter 1 Nutrition in Plants

PSEB 7th Class Science Guide Nutrition in Plants Textbook Questions and Answers

1. Fill in the Blanks:

(i) The process of obtaining and utilization of food by an organism is called ……………..
Answer:
nutrition

(ii) ………………. from the air is taken in through the tiny pores called stomata present on the surface of leaves.
Answer:
Carbon dioxide

(iii) ……………… is the initial product of photosynthesis.
Answer:
glucose (Carbohydrate)

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

(iv) The plants which depend on the food produced by other plants are called ………………..
Answer:
heterotrophs

2. State True or False:

(i) Carbohydrates is not an essential component of food.
Answer:
False

(ii) All green plants are autotrophs.
Answer:
True

(iii) Euglena is an organism that has both plant and animal like characters.
Answer:
True

(iv) Sunlight is not necessary for photosynthesis.
Answer:
False

3. Match the Column ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
1. Agaricus (a) Parasite
2. Rhizobium (b) Feaves
3. Chlorophyll (c) Feguminous plants
4. Cuscuta (d) Saprophyte

Answer:

Column ‘A’ Column ‘B’
1. Agaricus (d) Saprophyte
2. Rhizobium (c) Leguminous plants
3. Chlorophyll (b) Leaves
4. Cuscuta (a) Parasite

4. Choose the Correct Answer:

Question (i)
An Organism that fixes atmospheric nitrogen in the soil is :
(a) Amarbel
(b) Mushroom
(c) Rhizobium
(d) Chlorophyll
Answer:
(c) Rhizobium.

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

Question (ii)
The Organisms that cannot prepare their own food and depends on others for food are known as :
(a) Autotrophs
(b) Fleterotrophs
(c) Nutrients
(d) Minerals
Answer:
(b) Heterotrophs.

Question (iii)
Food factory of the plants is :
(a) Leaf
(b) Stem
(c) Root
(d) Flower
Answer:
(a) Leaf.

Question (iv)
Which of the following is a saprophyte ?
(a) Rhizobium
(b) Agaricus
(c) Cuscuta
(d) Protein
Answer:
(c) Cuscuta.

5. Very Short Answer Type Questions:

Question (i)
Define Nutrition.
Answer:
Nutrition. The act of obtaining and using food by the organism is called nutrition. Not all living things have the same food.

Question (ii)
What is photosynthesis ?
Answer:
Photosynthesis. It is a process in which food (carbohydrates) is produced by the plants. During this process, carbon dioxide and water are synthesized into glucose (simple carbohydrates) in the presence of sunlight by plant’s green matter (chlorophyll pigment).
Through this action green plants convert light energy into chemical energy.
Chemical Equation :
PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants 1

Question (iii)
Name the raw materials required for photosynthesis.
Answer:
Ingredients for photosynthesis :

  1. Carbon dioxide
  2. Water
  3. Solar Energy

Question (iv)
What are insectivorous plants ?
Answer:
Insectivorous plants. Plants that have a system for catching and digesting organisms are called insectivorous plants, such as pitcher plant. The leaves of these plants are transformed into pot compositions to catch insects.

6. Short Answer Type Questions:

Question (i)
What do you mean by parasitic mode of nutrition ?
Answer:
Parasitic Nutrition. Nutrition in which the parasitic organism harms another organism and derives its food from it is called parasitic nutrition.

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

Question (ii)
Explain symbiotic relationship.
Answer:
Symbiotic relationship. Two different organisms co-exist with each other and depend on each other for their nourishment, then it is called symbiotic relationship. In this kind of relationship both the beings get benefit from each other. Like the fungus found on the roots of many plants. The fungus gets nourishment from the roots of the plant and in turn absorbs water and minerals from the soil. Fungus and moss are a good example of symbiotic relationship. Here the fungi absorb water from the earth and in turn the algae provide food through photosynthesis.

Question (iii)
How does the pitcher plant catch insects ?
Answer:
PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants 2
The pitcher plant transforms its leaves into pot-like structures to catch insects. This pot-like creation has curly hair on the face. When an insect sits on it, it slips down and cannpt climb up again and falls to the bottom of the pot. The enzymes present at the bottom digest the insect.

7. Long Answer Type Questions:

Question (i)
How are nutrients replenished in the soil ?
Answer:
Regain of nutrients by soil. Plants continue to absorb water, minerals and other nutrients from the soil which leads to lack of nutrients in the soil. Time to time nutrition should be provided to the soil so that the fertility of the soil is maintained. Farmers usually recreate these nutrient deficiencies by mixing manure in the soil and Fertilizers (which contain one or more preservatives) to fulfil nutrients.
In forest the forest waste, leaves and animal waste is decomposed by decomposers into nutrients to improve fertility of the soil.

Question (ii)
What do you mean by nutrients ? Explain various modes of nutrition in plants.
Answer:
Nutrients. Carbohydrates, fats, proteins, vitamins and minerals are the main components of food. They help in the formation and function of the body and are called nutrients.

The main methods of nutrition in plants are :
(a) Autotrophic Nutrition. Those who prepare their own food from simple foods are called Autotrophs. This process of preparing food by such plants is called Autotrophic nutrition. All green plants are Autotrophic. In this method, chlorophyll, a green pigment present in plants, takes carbon dioxide and water from the air and makes food in the form of carbohydrates in the presence of solar energy. This action is called photosynthesis. Example-all green plants.

(b) Heterotrophic Nutrition. Some plants do not have green pigment (chlorophyll) and cannot make their own food, so they rely on food prepared by other plants for food. Such plants are called Heterotrophic plants and this method of obtaining food is called Heterotrophic nutrition. Example. Amar Bel.

PSEB Solutions for Class 7 Science Nutrition in Plants Important Questions and Answers

1. Fill in the Blanks:

(i) Green plants are called …………….. since they synthesise their own food.
Answer:
Autotrophs

(ii) The food synthesised by the plants is stored as ………………..
Answer:
Starch

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

(iii) In photosynthesis solar energy is captured by the pigment called …………….. .
Answer:
Chlorophyll

(iv) During photosynthesis plants take ……………… and produce …………….. .
Answer:
Carbondioxide, Oxygen

2. State True or False:

(i) Carbondioxide is released during photosynthesis.
Answer:
False

(ii) Plants which synthesise their food themselves are called saprotrophs.
Answer:
False

(iii) The product of photosynthesis is not a protein.
Answer:
False

(iv) During photosynthesis solar energy is converted into chemical energy.
Answer:
True

3. Match the Column I with Column II :

Column I Column II
(i) Chlorophyll (a) Bacteria
(ii) Nitrogen (b) Pitcher plant
(iii) Amarbel (c) Leaf
(iv) Animals (d) Parasite
(v) Insects (e) Heterotrophs

Answer:

Column I Column II
(i) Chlorophyll (c) Leaf
(ii) Nitrogen (a) Bacteria
(iii) Amarbel (d) Parasite
(iv) Animals (e) Heterotrophs
(v) Insects (b) Pitcher plant

4. Choose the Correct Answer:

Question 1.
The organisms which depend upon other organisms for food are called ……………..
(a) Symbionts
(b) Parasites
(c) Autotrophs
(d) Saprophytes.
Answer:
(b) Parasites.

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

Question 2.
Which part of the plant usually contains stomata ?
(a) Roots
(b) Stem
(c) Leaves
(d) Flower.
Answer:
(c) Leaves.

Question 3.
Which gas is released during photosynthesis ?
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) Hydrogen.
Answer:
(a) Oxygen.

Question 4.
What is the unit of living beings
(a) Organ
(b) Organ system
(c) Cell
(d) Tissue.
Answer:
(c) Cell.

Question 5.
What is the ultimate source of energy in the living beings ?
(a) Moon
(b) Sun
(c) Stars
(d) Planet.
Answer:
(b) Sun.

Question 6.
Name one eatable fungus.
(a) Alga
(b) Bacteria
(c) Rhizopus
(d) Mushroom.
Answer:
(d) Mushroom.

Question 7.
Plants breathe through:
(a) Epidermis
(b) Buds
(c) Stomata
(d) Root hairs.
Answer:
(c) Stomata.

Question 8.
What are green coloured thread like structures over the pond water called ?
(a) Fungi
(b) Algae
(c) Amoeba
(d) Paramecium.
Answer:
(b) Algae.

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

Very Short Answer Type Questions

Question 1.
Name the nutrients.
Answer:
Nutrients. Carbohydrates, vitamins, fats, proteins, minerals, roughage.

Question 2.
How do plants synthesise food ?
Answer:
Green plants synthesise their food material using carbondioxide, water and solar energy.

Question 3.
Name the various type of nutrition.
Answer:
Types of Nutrients. Autotrophic, Heterotrophic, Saprotrophic and Parasitic.

Question 4.
What are openings / pores in a leaf known as ?
Answer:
Stomata.

Question 5.
What is function of chlorophyll in a leaf ?
Answer:
Chlorophyll capture the energy of sunlight.

Question 6.
Which is ultimate source of energy for all living organisms ?
Answer:
Sun.

Question 7.
What are products of photosynthesis ?
Answer:
Carbohydrates and oxygen.

Question 8.
Name the various parts of plants which take part in photosynthesis.
Answer:
Green stems and green leaves.

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

Question 9.
Besides green leaves, which other coloured leaves are found in plants ?
Answer:
Deep red, violet or brown.

Question 10.
What is algae ?
Answer:
Algae It is a slimy, green patch found in pond or in stagnant water.

Question 11.
Do algae photosynthesis ? Why ?
Answer:
Yes, algae do photosynthesis as they contain chlorophyll.

Question 12.
From which elements are carbohydrates made up of ?
Answer:
Carbon, hydrogen and oxygen.

Question 13.
Name some four human parasites.
Answer:

  1. Mosquitoes
  2. lice
  3. bed bug
  4. leech.

Question 14.
Write one eatable fungus.
Answer:
Mushrooms.

Question 15.
Where does mould grow ?
Answer:
Moist and rainy areas.

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

Short Answer Type Questions

Question 1.
Write the definite word for the following:
(i) Weak stem parasitic plant.
(ii) A plant in which both Autotrophic nutrition and heterotrophic nutrition are found,
(iii) The holes through which gases are exchanged in the leaves.
Answer:
(i) Amar bel (Cuscuta)
(ii) Pitcher plant
(iii) Stomata

Question 2.
Differentiate autotrophic and heterotrophic nutrition.
Answer:
Differences between autotrophic nutrition and heterotrophic nutrition.

Autotrophic nutrition Heterotrophic nutrition
(1) Organisms prepare their own food by obtaining energy from sun. (1) Organisms obtain ready-made food from other plants or animals.
(2) It occurs in green plants and blue green algae. (2) It occurs in parasitic plants, fungi, most of bacteria and animals.

Question 3.
Why do coloured leaves photosynthesise when they are not green in colour ?
Answer:
Coloured leaves (red, brown etc.) do contain chlorophyll but large amount of red, brown pigment mask the green colour. So, they can photosynthesise.

Question 4.
How do fungus grow on the things ?
Answer:
Spores of fungi are present in air. When they land on wet and warm things, they germinate.

Question 5.
How do lichens show symbiotic relationship ?
Answer:
Lichens, a chlorophyll partner algae and non-green fungus live together. The fungus provides shelter, water and minerals to algae while algae provides food which is synthesised by it. So they both show symbiotic relationship.

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

Question 6.
Explain the parasitic relationship between Rhizobium and plants.
Answer:
PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants 3
Rhizobium is a bacterium that lives in nodules on the roots of legumes. It converts the nitrogen in the air into a usable form which is used by the plant and in return provides shelter and food to bacteria.

Question 7.
What do you understand by a parasites, saprophytes and symbiosis ? Give one example for each.
Answer:

  • Parasites. Those plants or animals which obtain their food from a host and also get shelter from it, are known as parasites, e.g. Cuscuta and Viscum etc.
  • Symbiosis. It is a type of relationship which is mutually beneficial for both the parents (host and parasite), e.g. Lichens are combination of algae and fungi. The fungus holds the algal cells in its mat of web-like hyphae and in return supplies water and dissolved minerals.
  • Saprophytes. Those organisms which grow on dead and decaying organic matter and obtain their food from decomposed bodies are known as saprophytes, e.g. Bacteria, mushrooms etc.

Question 8.
Distinguish between a parasite and a saprotroph.
Answer:
Differences between a parasite and saprotroph.

Parasite Saprotroph
(1) These organisms depend upon other living organisms for its food.
Example : Cuscuta, tape- worms, roundworms.
(1) These organisms obtain their food from dead organic matter.
Example : Fungi, bacteria.
(2) They produce special type of organs like suckers, hooks to obtain their food. (2) They secrete some enzymes to decompose complex molecules into simple form.

Question 9.
What are the conditions required for Autotrophic nutrition and its basic and by-products ?
Answer:
Photosynthesis is essential for Autotrophic nutrition which requires the following conditions : (1) sunlight (2) chlorophyll (green pigment), (3) carbon dioxide and (4) water.

The by-products of this process are: The basic products of photosynthesis are oxygen gas and glucose. Afterwards glucose is stored in the form of starch.

Long Answer Type Questions

Question 1.
Symbiosis is beneficial for both the partners, justify.
Answer:
PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants 4
Symbiosis. The type of association in which both the partners are benefited is called symbiosis.
In plants like lichens, there is an association of green algae and non-green fungus. The fungus forms a mat of web like hyphae to hold the algal cells. The fungal hyphae supply water and minerals to the algae. The algae can synthesise food for themselves as well as for the fungus.

PSEB 7th Class Science Solutions Chapter 1 Nutrition in Plants

Nutrition in Plants PSEB 7th Class Science Notes

  • For all living things such like: plants, animals, human beings food is necessary.
  • Main components of food are carbohydrates, fats, protein, vitamins and minerals which are important for the building and growth of human body.
  • The process of taking in food and using it for growth and development is called nutrition.
  • Different organisms require different types of nutrition.
  • On the basis of habits of intake of nutrients, nutrition can be divided into two types: (1) Autotrophic nutrition, (2) Heterotrophic nutrition.
  • Organisms which use simple inorganic matters and prepare their food on their own are called Autotrophs and the nutrition produced by them is called autotrophic nutrition.
  • All green plants and bacteria are Autotrophs.
  • Organisms which depend upon other organisms for food to survive are called Heterotrophs.
  • All animals, humans and certain types of fungi are heterotrophs.
  • Euglena is a type of organism which produces both autotrophic nutrition as well as heterotrophic nutrition.
  • Leaves are called the food factory of the plants.
  • Leaves produce their food by photosynthesis. During photosynthesis in green plants, the green coloured pigments (chlorophylls) are capable of trapping sunlight and take carbon dioxide (CO2) from the air in the
  • presence of water to produce food in the form of carbohydrates.
  • The leaves of the plants have tiny pores on their top layer, through which the carbon dioxide (taken in) and oxygen (given out) are exchanged and these exchange pores are called stomata.
  • Stomatas are surrounded by the guard cells.
  • Soil provides water and minerals to plants, which are absorbed by the roots of the plants through Xylem tissues present in roots and further sent to other parts of the plant.
  • Sun is the main source of energy for all living organisms.
  • In photosynthesis process the energy of sun is converted into chemical energy.
  • The leaves of some plants are not green in colour but of some other colour as for example: red leaves of coleus, red cabbage has violet leaves. Such leaves also show photosynthesis because they also contain chlorophylls but lesser in amount than green plants.
  • The basic products of photosynthesis are oxygen and glucose.
  • Heterotrophs are divided into four types:
    1. Decomposers
    2. Parasites
    3. Insect eaters
    4. Symbiotic
  • The organisms that get nourishment from the body of other living beings are called parasites.
  • Organisms that depend on dead bodies and rotten substances for their nourishment, are called decomposers.
  • In symbiotic relationship, two types of organisms depend on each other for food, in which both the organisms are benefited.
  • Dead and decaying plants and animals are decomposed by the decomposers which provide essential nutrients to the soil.
  • Nutrients: The main components of food such as carbohydrates, fats, proteins, vitamins and minerals that help in growth and development of body are called nutrients.
  • Self- nutrition: Organisms that make their own food from simple substances are called self-nourishment. This type of nutrition is called autotrophic nutrition.
  • Heterotrophic nutrition: Organisms that can’t prepare their own food but depend on other organisms are called Heterotrophs and this type of nutrition is called Heterotrophic nutrition.
  • Dead food: A diet in which dead creatures or rotten substances are providing food to other organisms.
  • Parasites: Organisms that depend on other plants and organisms for food are called parasites.
  • Photosynthesis: This is an activity in which the leaves of a plant contain green colour pigment- chlorophyll, carbon dioxide of the air and water in the presence of sunlight prepare food in the form of carbohydrates. Here solar energy is converted in the chemical energy.
  • Chlorophyll: This is a green pigment that is present in plants. This is important for plants to prepare their own food.
  • Carbohydrates: A type of micronutrient that is present in many foods such as sugar, starch and fiber. Our body needs these micronutrients to stay healthy.
  • Stomata: Stomata are found on the outer surface of the aerial parts of the plant. Maximum amount of stomata is found on leaves. Gases are exchanged through Stomata (holes).
  • Host: The plants or organisms on which the parasite depends for its food is called the host.
  • Chemical Fertilizer: This is a factory made chemical (a mixture of inorganic salts). It contains a lot of nutrients for plants. It fulfils the deficiency in the soil so that the soil remains fertile.
  • Rhizobium: A Bacterium found in the roots and buds of leguminous plants. It makes the nitrogen in the air usable, which is used by plants and in return, plants provide shelter and food to this bacteria.

Punjab State Board PSEB 7th Class Science Book Solutions Chapter 1 Nutrition in Plants Textbook Exercise Questions and Answers.

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

PSEB Solutions for Class 7 Science Chapter 2 Nutrition in Animals

Science Guide for Class 7 PSEB Nutrition in Animals Intext Questions and Answers

Think and Answer (Textbook Page No. 12)

Question 1.
Name the solution secreted by the Salivary glands of mouth.
Answer:
The saliva Juice is released by the salivary glands in the mouth.

Question 2.
What changes are seen in starch on adding iodine solution ?
Answer:
Post-iodine solution added to starch iodine solution turns purple or blue.

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

Question 3.
In which form the starch is converted after digestion in mouth ?
Answer:
Saliva is released by the salivary glands in the mouth which contains an enzyme called amylase. This enzyme converts starch into sugar.

Think and Answer (Textbook Page No. 13)

Question 1.
Give other name for cutting teeth.
Answer:
Incisors are also called sharp teeth.

Question 2.
Which age group has both premolars and molars ?
Answer:
Pre-molar and molar teeth begin to break at the age of 50 years and above.

Question 3.
What is the maximum number of teeth present in an adult ?
Answer:
Adults over the age of 30 have a total of 32 teeth of all types in their mouths.

Think and Answer (Textbook Page No. 14)

Question 1.
At which region of the tongue sour taste is felt ?
Answer:
At around 3/4th part of the tongue from the starting i.e. a bit ahead of middle of the tongue the sour taste is experienced.

Question 2.
Why don’t we feel bitter taste at front part of the tongue ?
Answer:
The front part of tongue is free to move in all directions and this part only helps in chewing food and mixing saliva. The four glands on tongue are sweet, salty, sour and a little. Only sweet taste is experienced in the front part of the tongue whereas bitter taste is experienced in the last part of the tongue.

PSEB 7th Class Science Guide Nutrition in Animals Textbook Questions and Answers

1. Fill in the Blanks:

(i) The animals that eat both plants as well as animals are called ………………..
Answer:
omnivorous

(ii) ……………… of the food in human beings start in mouth and is completed in the ……………. .
Answer:
digestion, small intestine

(iii) ………………… is the largest gland in human beings.
Answer:
liver

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

(iv) The large intestine absorb excess ………………… and ……………… from undigested food
Answer:
excess water, salt

2. State True or False:

(i) The tongue helps in mixing of food with saliva.
Answer:
True

(ii) In a humans digestion is completed in the stomach.
Answer:
False

(iii) Cud chewing animals are called ruminants.
Answer:
True

(iv) Amoeba captures food particles with the help of pseudopodia.
Answer:
False

3. Match the Column ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
1. Ruminant (a) Bile
2. Carbohydrates (b) Store undigested food
3. Gall bladder (c) Glucose
4. Small intestine (d) Cow
5. Rectum (e) Digestion is completed

Answer:

Column ‘A’ Column ‘B’
1. Ruminant (d) Cow
2. Carbohydrates (c) Glucose
3. Gall bladder (a) Bile
4. Small intestine (e) Digestion is completed
5. Rectum (b) Store undigested food

4. Choose the Correct Answer:

Question (i)
Animals that eat only plants are called:
(a) Carnivores
(b) Herbivores
(c) Omnivores
(d) Saprophytes
Answer:
(b) Herbivorous.

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

Question (ii)
Extracellular digestion occurs in:
(a) Parasites
(b) Carnivores
(e) Saprophytes
(d) Herbivores
Answer:
(e) Saprophytes.

Question (iii)
The process of taking food into the body is called:
(a) Ingestion
(b) Digestion
(e) Absorption
(ri) Egestion
Answer:
(a) Ingestion.

Question (iv)
Secretion of Liser is:
(a) Proteins
(b) Bile
(c) Carbohydrates
(d) Saliva
Answer:
(b) Bile.

Question (v)
Nutrition in Amoeba is:
(a) Parasitic
(b) Holozoic
(c) Saprophytic
(d) Assimilation
Answer:
(c) Saprophytic.

5. Very Short Answer Type Questions:

Question (i)
What is holozoic nutrition ?
Answer:
PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals 1
Holozoic nutrition. During this type of nutrition Complex food is taken into the body and then broken down into simple soluble compounds with the help of enzymes; which are absorbed by the body, e.g. Amoeba, human,etc.

Question (ii)
What do you mean by absorption ?
Answer:
Absorption.
During this process the digested food is absorbed through the walls of the small intestine. After this the digested food goes into the blood vessels. On the inner walls of the small intestine, there are a large number of eruptions, called Villi. These finger like projections increase the absorption area of intestine.

Question (iii)
Define assimilation.
Answer:
Automation. Food absorbed by intestine reaches different parts of the body through the blood. This is called Automation.

Question (iv)
Name the parts of alimentary canal.
Answer:
The different parts of the Digestive system are as follows:

  1. Oral cavity
  2. Food Pipe
  3. Stomach
  4. Small intestine
  5. Large intestine
  6. Rectum
  7. Anus.

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

6. Short Answer Type Questions:

Question (i)
What do you mean by milk teeth and permanent teeth ?
Answer:
(a) Milk teeth. Two sets of teeth develop during a person’s lifetime. The first set consists of 20 small teeth, also called milk teeth. They grow during infancy and break down at 6 and 8 years of age.

(b) Permanent Teeth. Between the ages of 6 to 8 years, permanent teeth (32) appear after the fall of the milk teeth. Permanent teeth begin to fall out between the ages of 50 and 60.

Question (ii)
Write four types of human teeth and their functions.
Answer:
The four types of teeth found in post-humans and the four types of teeth found in functional humans are given below:
PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals 2

7. Long Answer Type Questions:

Question (i)
Explain nutrition in Amoeba with the help of a diagram.
Answer:
PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals 3
Amoeba.
Amoeba is a microscopic single celled organism found in pond water. It has a cell membrane, a rounded, dense nucleus and many small bubbles- like vacuoles. Amoeba constantly changes it’s shape and position. It moves with it’s virtual feet (called pseudopodia).These are finger like structures which help in movement. During food intake, the membrane between the two virtual legs melts around the food and the food particle get trapped into a vacuole and there is a leakage of enzymes inside it, which break it down in simpler substances from which nutrients are absorbed. Undigested food particles are abandoned by a similar process.

Question (ii)
label the following diagrams:
PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals 4
Answer:
PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals 5

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

PSEB Solutions for Class 7 Science Nutrition in Animals Important Questions and Answers

1. Fill in the Blanks:

(i) The main steps of digestion in humans are ……………, ……………, ………….., ………… and ………… .
Answer:
ingestion, digestion, absorption, assimilaton, egestion

(ii) The largest gland in human body is ………………
Answer:
liver

(iii) The stomach releases hydrochloric acid and ………………. juices which act on food.
Answer:
digestive

(iv) The inner wall of small intestine has many finger like outgrowths called ……………… .
Answer:
villi

(v) Amoeba digests its food in the …………… .
Answer:
food vacuole

2. State True or False:

(i) Digestion of starch starts in the stomach.
Answer:
False

(ii) The tongue helps in mixing food with saliva.
Answer:
True

(iii) The gall bladder temporarily stores bile.
Answer:
True

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

(iv) The ruminants bring back swallowed grass into their mouth and chew it for some time.
Answer:
True

3. Match the Column I with Column II:

Column I (Food Components) Column II (Products of Digestion)
1. Carbohydrate (a) Fatty acids and glycerol
2. Proteins (b) Sugar
3. Fats (c) Amino acids.

Answer:

Column I (Food Components) Column II (Products of Digestion)
1. Carbohydrate (b) Sugar
2. Proteins (c) Amino acids
3. Fats (a) Fatty acids and glycerol.

4. Multiple Choice Questions:

Question (i)
Name the process of breaking down of complex substances of food into simpler forms.
(a) Assimilation
(b) Ingestion
(c) Digestion
(d) Egestion.
Answer:
(c) Digestion.

Question (ii)
Name the largest digestive gland of human beings ?
(a) Salivary
(b) Pancreas
(c) Liver
(d) Intestinal.
Answer:
(c) Liver.

Question (iii)
Which acid kills bacteria in stomach ?
(a) Sulphuric
(b) Nitric
(c) Hydrochloric
(d) Phosphoric.
Answer:
(c) Hydrochloric.

Question (iv)
Of the following, in which animal rumen is found?
(a) Cow
(b) Dog
(c) Lion
(cI) Cheetah.
Answer:
(a) Cow.

Question (v)
What is the length of small intestine?
(a) 10.5 m
(b) 4 m
(c) 3 m
(d) 7.5 m.
Answer:
(d) 7.5 m.

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

Question (vi)
Movement of food in alimentary canal is called:
(a) Locomotion
(b) Pumping
(c) Peristalsis
(d) Sliding.
Answer:
(c) Peristalsis.

Question (vii)
Which is the simplest carbohydrate?
(a) Glucose
(b) Sucrose
(c) Starch
(d) All of the above.
Answer:
(a) Glucose.

Question (viii)
Where is Saliva produced?
(a) Stomach
(b) Pancreas
(c) Salivary Glands
(d) None of the above.
Answer:
(c) Salivary Glands.

Very Short Answer Type Questions

Question 1.
What is food pipe ?
Answer:
Food pipe. It consists of orla cavity oesophagus, stomach, small intestine, large intestine, anus etc.

Question 2.
Write the names of digestive glands.
Answer:

  1. Salivary glands
  2. Liver
  3. pancreas.

Question 3.
What are the different parts of the digestive system ?
Answer:
Digestive juices and food pipe.

Question 4.
When does temporary or milk teeth fall ?
Answer:
Upto the age of six or eight years.

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

Question 5.
What is length of small intestine ?
Answer:
7.5 metre (approx.)

Question 6.
What length of large intestine ?
Answer:
1.5 metre (approx.)

Question 7.
Name different types of teeth found in human body.
Answer:
Canines, Incisors, Molars, Premolars.

Question 8.
Which teeth are for cutting and bitting ?
Answer:
Incisors.

Question 9.
Which teeth help in tearing the flesh of prey in animals ?
Answer:
Canines.

Question 10.
What is function of molars and premolars ?
Answer:
Chewing and grinding.

Question 11.
What is tongue ?
Answer:
Tongue. Tongue is a fleshy part of body.

Question 12.
How does tongue taste ?
Answer:
With the help of taste buds.

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

Question 13.
What food items are responsible for tooth decay ?
Answer:
Chocolates, Cold drinks, Sweets etc.

Question 14.
Which acid present in stomach kills germs ?
Answer:
Hydrochloric acid.

Question 15.
Which component of food is broken down by saliva in mouth ?
Answer:
Starch.

Short Answer Type Questions

Question 1.
What is Villi ? Where are they present and what are their functions?
Answer:
Villi. Finger-like raised structures in the inner wall of the small intestine are called villi. These are found in the small intestine. Its main function is to absorb digested food.

Question 2.
Where is bile juice made ? Which food components are digested by it?
Answer:
Bile juice is made in the liver and accumulates temporarily in the gallbladder. Its main function is to digest fats.

Question 3.
Write the name of the carbohydrate which is digested by Ruminants but not by humans. Also give reason.
Answer:
Cellulose can be easily digested by Ruminant. A type of bacterium that helps in the digestion of cellulose is found in a sac between the small and large intestines in the rumen of ruminants only. This is the reason humans cannot digest cellulose.

Question 4.
What is the reason that we get energy from glucose immediately?
Answer:
Glucose is a simple form of carbohydrate that is easily absorbed by the body. It dissolves easily in the blood and gives energy immediately.

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

Question 5.
Which part of the digestive canal is involved in:
(i) Absorption of food …………. .
(ii) Chewing of food ………………. .
(iii) Killing of bacteria ……………. .
(iv) Complete digestion of food …………… .
(v) Formation of faeces ……………….. .
Answer:
(i) Small intestine
(ii) Buccal cavity
(iii) Stomach
(iv) Small intestine
(v) Large intestine.

Question 6.
Write one similarity and one difference between the nutrition in amoeba and human beings.
Answer:
Similarity in the nutrition in amoeba and human beings:
(a) Digestion of food
(b) Release of energy
Difference in nutrition in amoeba and human beings.
Human beings have a well developed digestive system while amoeba has only food vacuole for digestion.

Question 7.
Can we live only by eating vegetable/grass ? Discuss.
Answer:
Raw green vegetables are rich source of minerals, cellulose and vitamins etc. Apart from, this body needs carbohydrates, fats and proteins. So only vegetables can not provide all these for sustaining etc.

Question 8.
What is digestion and what are its main objectives?
Answer:
The breakdown or conversion of complex foods into simple foods is called digestion.
Purpose of Digestion.

  • Breaking of large particles into smaller particles so that they can pass through the
    membranes.
  • Conversion of insoluble substances into soluble substances so that the solution can reach all the places.
  • Complete conversion of complex foods into simple substances so that they can be absorbed by cells.

Question 9.
What is a tooth cavity and why does it occur ?
Answer:
Tooth cavity and toothache. By eating too much sweets and not keeping our teeth clean, we invite bacteria which causes damage to our teeth. If we do not keep our teeth clean, food particles get stuck in the teeth and by attacking them, the bacteria start decomposing the food particles which results in the formation of acid. This acid destroys tooth enamel and causes tooth decay. So we should always brush our teeth after eating food and sweets.

Long Answer Type Questions

Question 1.
Describe the digestive system of man.
Answer:
The digestive system of man includes the following organs :

  • Mouth. The mouth is first part of food pipe. It contains tongue, teeth and salivary glands. The tongue tastes the food. The salivary glands secrete saliva which lubricates the food. The teeth break the solid food into smaller fragments.
  • Oesophagus. It is a tubular structure from mouth to stomach. It takes the food from mouth to stomach.
  • Small intestine. It is a coiled tube and is the longest part of food pipe. The digestion of food is completed here with the help of enzymes present in the secretions of liver and pancreas.

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals 6

  • Large intestine. It absorbs water. The undigested food or faecal matter is stored temporarily and finally removed from the body through anus.

Question 2.
What is the process of Rumination ? How is digestion done in Ruminants ? Explain.
Answer:
Rumination. Grass eating animals chew the cud and are called Ruminants. Cows, buffaloes, camels and deer are a few examples. Their stomach is made up of four cells. The first cell is the rumen, which is the largest part of the stomach. The animal first swallows the food and stores it in the rumen. This half-digested food is called cud. Later, the cud returns to the animal’s mouth in the form of small lumps and the animal continues to chew it slowly. This process is called rumination. Such animals are called ruminants.

During rumination, the cellulose in the food breaks down into simple compounds. It is then digested in liquid form in the other three cells. The oesophagus of ruminant animals has a sac- like structure between the small intestine and the large intestine called the Caecum, where there are some bacteria that help digest grass straw.
PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals 7

PSEB 7th Class Science Solutions Chapter 2 Nutrition in Animals

Nutrition in Animals PSEB 7th Class Science Notes

  • Animals do not make their own food like plants. They get their food directly or indirectly from plants.
  • Animals eat complex foods and then break them down into simpler substances.
  • Different animals require nutrients, different ways of consuming food and different ways of using food in the body.
  • Those who eat only plants are called vegetarians.
  • Animals that only feed on other animals are called carnivores.
  • Animals that eat both plants and other animals are called omnivorous animals.
  • Different types of animals have different ways of getting food.
  • There are three types of nourishment : (1) Decomposer nutrition (2) Parasitic nutrition (3) Animal nutrition.
    During animal nutrition, complex food is transported to the body where it is broken down into simple soluble substances (compounds) with the help of enzymes, which are absorbed by the body.
  • Five stages during the process of receiving food are :
    (a) Food intake (b) Digestion (c) Absorption (d) Self-adaptation (e) Excretion.
  • The human digestive system includes the mouth cavity, food pipe, stomach, small intestine, large intestine, Rectum and Anus.
  • There are four types of teeth in the human mouth.
    (a) Incisors, (b) Canines, (c) Pre-molars, (d) Molars teeth
  • Food is digested starting from the mouth and up to the small intestine.
  • Digested food is transmitted through the blood to different parts of the body.
  • Absorption of water and some salts occurs in large intestine.
  • Undigested and unabsorbed food remains in the rectum in the form of feces and is then excreted through anus.
  • Carnivores: Animals that only feed on other animals are called carnivores.
  • Omnivorous: Animals that eat plants and other animals as food are called omnivorous animals.
  • Eating: The act of taking food into the body is called eating.
  • Digestion: This is the biological process during which complex substances are broken down into simpler substances. Enzymes (chemicals) that leak from the glands in the body help in this digestive process. Digestion starts from the mouth cavity and ends in a small intestine.
  • Absorption: This is the stage of food acquisition in which the digested food is absorbed through the inner walls of the small intestine.
  • ‘ Excretion: Undigested food passes out of the oesophagus. This process is called excretion.
  • Mouth cavity: The food received through the mouth then goes into the mouth cavity. It is the part that comes after teeth area.
  • Enamel: A strong protective substance on the teeth is a layer of enamel.
  • Food Pipe: It is the longest part in oesophagus, extending from mouth to the anus. Here enzymes break down complex food into simple molecules.
  • Gallbladder: This is a pouch that sits just under the liver, it stores the bile produced by the liver.
  • Caecum: A diaphragm-like structure between the small intestine and the large intestine is called the caecum organ.
  • Bile Juice: Liver is the largest gland of our body from which leakage occurs which accumulates in the
  • gallbladder: This leakage is called bile juice.
  • Ruminants: Grass-eating animals such as cows, buffaloes, are called ruminants.
  • Automation: Food absorbed by intestines is transported through the blood to different parts of the body. This action is called automation.

Punjab State Board PSEB 7th Class Science Book Solutions Chapter 2 Nutrition in Animals Textbook Exercise Questions and Answers.