NCERT Solutions for Class 5th The World Around Us Chapter 1 Closing questions — Let us reflect

Because most of the water on Earth is salty sea water, and salty water is of no use for drinking or for growing crops.

Think of the picture on page 4.

1. A glass of 200 ml stands for all the water on Earth.
2. The freshwater in it is only 5 ml — one teaspoon.
3. The other 195 ml is salty ocean water.
4. And even that one teaspoon is not all easy to reach. A large part of it is locked up as ice in glaciers and ice caps, and much of the rest is groundwater deep below us.

Because water gives them everything they need to stay alive — a drink, food, a home and a safe place to raise their young. No living thing can survive without water, so life gathers wherever water is.

• Water to drink. Every animal must drink. A pond or a river means it does not have to travel far.
• Food. Plants grow well where there is water, and where plants grow, insects, birds and animals come to eat. The pond itself is full of fish, frogs and insects for the bigger animals.
• A home. Fish, turtles, water snakes and water scorpions live in the water. Reeds and lotus leaves at the edge give birds a place to nest and small creatures a place to hide.
• Cooler air. The air near a water body stays cooler and more pleasant, especially in summer.
• For people. Villages and cities grow near rivers, because people need water for drinking, for farming, for animals, for washing, and for travelling by boat.

There would be a severe water shortage — a drought. Wells and ponds would dry up, crops would fail, and people and animals would suffer.

What would happen, in order:

1. First few months. Ponds and small streams dry up. The soil becomes hard and cracked.
2. After that. The groundwater is not being recharged, so its level falls. Handpumps start pulling air. Wells go dry.
3. In the fields. Crops dry up and die. Farmers get no harvest and no income.
4. Food and prices. Grain and vegetables become scarce, so they become expensive.
5. Animals. Cattle have no grass and no water. Wild animals leave the area or die.
6. People. Families walk long distances to fetch water. Water has to be sent in by tankers. Some people may leave the village to look for work elsewhere.
7. Health. The little water left is often dirty, and dirty water causes illness.

In a forest most of the rainwater soaks into the ground. In a city most of it runs off the hard surfaces and rushes into drains.

Yes. A water-wise building does three things: it catches the rain that falls on it, it uses less water every day, and it uses water twice wherever that is safe.

Sample answer — my water-wise school

1. Catch the rain

• Gutters along every roof edge, leading into one downpipe.
• A big covered storage tank at ground level, with a simple filter of net, gravel and sand at the inlet.
• A recharge pit beside the tank. When the tank is full, the extra water goes into this pit and sinks down to become groundwater.
• A small pond in the school ground to hold rainwater and let it seep in.

2. Use less

• Push taps that close by themselves, so no tap is left running.
• A monitor from each class checks every tap and pipe once a week and reports leaks the same day.
• Small-flush or dual-flush toilets.
• A water-level indicator on the overhead tank so it never overflows.
• Mugs beside the washbasins, and buckets instead of hosepipes for washing.

3. Use it twice

• Water left in drinking bottles at the end of the day goes into the plant pots, not down the drain.
• The waste water from the RO machine is collected and used to wash floors and water the garden.
• Drip pipes water the kitchen garden slowly, drop by drop, in the early morning.

4. Keep the ground open

• Grass, soil and trees instead of full cementing, so rain can soak in.
• Paving blocks with gaps in the walking paths.

5. Tell everyone

• Painted signs at every tap: “Close me tight”.
• A chart on the notice board showing how many litres the school saved this month.

Take a square sheet of paper — any colour. Fold on a hard, flat table and press every crease firmly with your thumbnail. Here are the six steps shown in the pictures on page 20.

1. Step 1 — Fold it in half. Bring the bottom edge up to meet the top edge. Press the crease and open it again. You now have one line across the middle.
2. Step 2 — Make a flat band. Fold the top edge down to the middle line, and the bottom edge up to the middle line. The square becomes a long band with two layers.
3. Step 3 — Open the middle and press. Put a finger inside the band and push the middle apart, so that the two ends flare out. The paper now looks like a bow, wide at the ends and pinched in the middle.
4. Step 4 — Fold one end into a fin. Take one end and fold its corner outwards and upwards so that a triangle stands up. That triangle will be the fin on the fish's back.
5. Step 5 — Make the tail. At the other end, fold the two corners outwards so that they form two sharp points. Press them flat. It is beginning to look like a fish lying on its side.
6. Step 6 — Finish the fish. Turn the whole shape so the body is upright, the pointed end is at the back and the flat end is in front. Flatten it once more. Now draw an eye and a smiling mouth on the front. Your paper fish is ready.