Table of Contents


Answer the following questions:-

1. What is a terrarium?

Answer – It is an artificial enclosure for keeping small house plants.

2. What is the water cycle?

Answer – The process by which water continually changes its form and circulates between oceans, atmosphere, and land is known as the water cycle.

3. What are the major sources of freshwater?

Answer – The major sources of freshwater are rivers, ponds, springs, and glaciers.

4. Why the sea or ocean water is salty?

Answer – The water of the oceans is salty or saline as it contains a large number of dissolved salts.

5. What is the chemical name of common/table salt?

Answer – Sodium Chloride

6. What is salinity?

Answer – Salinity is the amount of salt in grams present in 1000 grams of water.

7. What is the average salinity of an ocean?

Answer – The average salinity of the oceans is 35 parts per thousand.

8. What percentage of water is saline?

Answer – 97.3%

9. When do we celebrate World Water Day?

Answer – 22nd March

10. What are different kinds of movements in the ocean?

Answer – The movements that occur in oceans can be broadly categorized as:

Waves, tides, and currents.

11. What are waves?

Answer – When the water on the surface of the ocean rises and falls alternately, they are
called waves.

12. How waves are related to the strength of the wind?

Answer – Directly proportional.

13. What is Tsunami?

Answer –An earthquake, a volcanic eruption, or underwater landslides can shift large amounts of ocean water and as a result, a huge tidal wave called a tsunami forms.

14. Which place of India got submerged in the 2004 Tsunami?

Answer – Indira Point in the Andaman and Nicobar Island.

15. What are tides?

Answer – The rhythmic rise and fall of ocean water twice a day is called a tide.

It is high tide when water covers much of the shore by rising to its highest level. It is low tide when waterfalls to its lowest level and recedes from the shore.

16. What causes the tides?

Answer – The strong gravitational pull exerted by the sun and the moon on the earth’s surface causes the tides.

17. What is spring tide?

Answer – The water of the earth closer to the moon gets pulled under the influence of the moon’s gravitational force and causes high tide. During the full moon and new moon days, the sun, the moon, and the earth are in the same line and the tides are highest. These tides are called spring tides.

18. What is the neap tide?

Answer – when the moon is in its first and last quarter, the ocean waters get drawn in diagonally opposite directions by the gravitational pull of the sun and moon resulting in low tides. These tides are called neap tides

19. List some ways in which high tides are useful.

Answer –

  • High tides help in navigation. They raise the water level close to the shores. This helps the ships to arrive at the harbour more easily.
  • The high tides also help in fishing. Many more fish come closer to the shore during the high tide. This enables fishermen to get a plentiful catch.
  • The rise and fall of water due to tides is being used to generate electricity in
    some places.

20. What are Ocean Currents?

Answer – Ocean currents are streams of water flowing constantly on the ocean surface in definite directions. The ocean currents may be warm or cold.

21. Where does the warm ocean current originate and move?

Answer – Generally, the warm ocean currents originate near the equator and move towards the poles.

22. Where does the cold ocean current originate and move?

Answer – The cold currents carry water from polar or higher latitudes to tropical or lower latitudes.

23. Give one example of each warm and cold ocean current.

Answer – Cold Ocean current – Labrador Ocean current

Warm Ocean current – the Gulf Stream

24. Where you can found the best fishing ground in the world?

Answer – The place where cold and warm ocean current meets e.g. Seas around Japan and the eastern coast of North America

25. The place where cold and warm ocean current meets is difficult for navigation. Why?

Answer – The areas where a warm and cold current meets also experience foggy weather making it difficult for navigation.

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