This PSEB 7th Class Social Science Notes Chapter 4 Ocean will help you in revision during exams.
PSEB 7th Class Social Science Notes Chapter 4 Ocean
→ Oceans: The big reservoirs of water on earth are known as oceans. The Pacific Ocean, Atlantic Ocean, and Indian ocean are the main oceans.
→ Pacific Ocean: It is the longest and deepest ocean on earth. It is so deep that even the highest peak Mt. Everest can sink in it.
→ Seas: Every ocean is divided into small parts. These small parts are known as seas.
→ Speeds of Ocean Water: The ocean water has three speeds waves, currents, tides.
→ Waves: Ripples in ocean water caused by winds blowing over the sea.
→ Current: When the ocean water starts moving in a specific direction it is known as oceanic current.
→ The speed of oceanic current normally ranges from 2 km/hr to 10 km/hr.
→ Tides: Regular rise and fall of ocean water as a result of the gravitational pull of the sun and the moon. It happens twice in 24 hrs.
→ High tide and Low tide: On a full moon day the tides of the sea rise to the highest level. It is called high tides.
→ When the oceanic tides rise to the lowest level it is called low tides.
→ Water cycle: Unending movement of water between hydrosphere, atmosphere, lithosphere, and back to the hydrosphere.
→ Groundwater: Water that soaks underground, roots of plants help water go underground.
→ Transpiration: Water vapours are returned to the atmosphere by plants.
→ Water budget: The balancing of precipitation on the ground with evaporation and transpiration in the atmosphere.
→ Waves: Ripples in ocean water caused by winds blowing over the sea.