Class VII - Water

1. tides When the moon is in its first and last quarter, lower tides called neap tides occur.
3. Run off is one of the stages illustrated in the diagram of the water cycle.
6. The sun’s heat causes evaporation of water into vapour.
7. tides During the full moon and new moon days, the highest tides, known as spring tides, occur.
8. Our earth is compared to a terrarium because the same water exists today as it did centuries ago.
10. The water of the oceans is saline as it contains large amounts of dissolved salts.
13. When the water vapour cools down, it condenses and forms clouds.
15. When the water on the surface of the ocean rises and falls alternately, they are called waves.

2. From clouds, water may fall on the land or sea in the form of precipitation like rain, snow or sleet.
4. Oceans contain 97.3% of the total water on Earth, which is mostly salty.
5. The process by which water continually changes its form and circulates between oceans, atmosphere and land is known as the water cycle.
9. The major sources of fresh water are rivers, ponds, springs and glaciers.
11. A tsunami is a huge tidal wave that can be caused by an earthquake or underwater landslide.
12. The rhythmic rise and fall of ocean water twice in a day is called tide.
14. currents Ocean currents are streams of water flowing constantly on the ocean surface in definite directions.