Question

About 97% of all the water on Earth is salty water in the oceans.

In a class activity, a 2000 L tank of water stands for all the water on Earth. If about 3% of Earth's water is fresh water, how many litres of the tank stand for fresh water?

Explain with an example how the cryosphere and the hydrosphere are linked.

A school in Jaipur decides to harvest rainwater from its flat roof. The roof area is 200 square metres and the average yearly rainfall there is about 0.8 m (800 mm). The collected water is stored in an underground tank and used for gardening and toilets. The students also fix leaking taps and put up posters on saving water. (Use: volume of rain on roof = roof area × rainfall height; 1 cubic metre = 1000 L.)