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“Catch water where it falls” is the basic idea behind (a) recycling of water (b) making dams to store water (c) rainwater harvesting (d) condensation of water vapour.

(c) rainwater harvesting Rainwater harvesting is a method used to collect rainwater. By storing the water, we can increase the availability of... View Article

Floods causes extensive damage to (a) crops (b) property and human life (c) domestic animals (d) all of the above

(d) all the above A flood is an overflow of water on land. Sometimes a river might receive extra water, either from heavy rains or other... View Article

Wells are fed by (a) pond water (b) lake water (c) rain water (d) groundwater

(d) groundwater When it rains, the water fills up the lakes and ponds. Some water gets absorbed by the soil and ground and the remaining water... View Article

Clouds are (a) tiny drops of water floating in air (b) mixture of dust and water vapour (c) particles of water vapour (d) rain drops in air.

a) Tiny drops of water floating in the air. Clouds are an important part of the earth’s weather and climate.Clouds form from water... View Article

Transpiration is a process in which plants (a) receive water from soil (b) absorb water vapour from air (c) prepare food from water (d) release water vapour

(d) release water vapour. During the process of transpiration, water molecules in the plant tissues are removed from the aerial parts of the... View Article

In which of the following case evaporation of water will be slowest? (a) A tray of water kept in sunlight. (b) A kettle of water kept on a burner. (c) A glass of water kept in a room. (d) A bucket of water kept on rooftop.

c) Glass of water kept in a room. A glass of water kept in a room. Evaporation is directly proportional to temperature. That is with the rise... View Article

Water in our tap comes from a (a) river (b) lake (c) well (d) river, lake or well

(d) river, lake or well We get water from taps in our home. This tap water is drawn either from a river, lake or well and is then supplied... View Article

The quantity of water required to produce one page of your book is (a) one bucket (b) ten buckets (c) two glasses (d) few drops.

c) Two glasses Almost two glasses of water is required to make one sheet of paper. Uses of water Possibly the most substantial everyday use of... View Article

In which of the following activities will you use minimum amount of water? (a) Bathing (b) Brushing teeth (c) Washing clothes (d) Mopping a room

b) Brushing teeth Water is one of the necessities for every living being and we cannot imagine a life without water. It is the natural... View Article

Which of the following activity does not involve use of water? (a) Washing clothes (b) Bathing (c) Cleaning utensils (d) Drying wet clothes

d) Drying wet clothes Water gets converted into vapour form in drying wet clothes.Whereas washing, bathing and cleaning utensils are the... View Article

On a Sunday morning, Paheli’s friend visited her home. She wanted to see some flowering plants in the nearby garden. Both of them went to the garden. While returning from the garden they also observed some flowering plants on the roadside. But to their surprise, they found that the leaves and flowers of these roadside plants were comparatively very dull. Can you help them to know why?

Paheli and her friend observed plants will dull leaves and flowers because of the air quality present in the open area. Air is polluted on... View Article

Paheli kept some water in a beaker for heating. She observed that tiny bubbles appeared before the water started to boil. She boiled the water for about 5 minutes and filled it in a bottle up to the brim and kept the bottle airtight till it cooled down to room temperature. (a) Why did the tiny bubbles appear? (b) Do you think tiny bubbles will appear on heating the water taken out from the bottle? Justify your answer.

Paheli had boiled out the complete water that means all the air from the water escaped out, so on boiling the boiled cooled water will not make... View Article

Write just a few sentences for an imaginary situation if any of the following gases disappear from the atmosphere. (a) Oxygen (b) Nitrogen (c) Carbon dioxide

(a) If oxygen disappear from the atmosphere then— There will be no life on the earth. Burning will be not possible due to disappear of oxygen.... View Article

Explain the following observations very briefly. (a) A firki does not rotate in a closed area. (b) The arrow of weathercock points towards a particular direction at a particular moment. (c) An empty glass, in fact, is not empty. (d) Breathing through the mouth may harm you.

(a) Firki rotates when the force is applied to the blades of the first. The force is applied on the blades of the first by the moving air called... View Article

Garima observed that when she left her tightly capped bottle full of water in open sunlight, tiny bubbles were formed all around inside the bottle. Help Garima to know why it happened?

Air dissolved in the water escapes in the form of tiny bubbles because the sun was giving heat energy to the bottle. When water is boiled, the... View Article

A list of words is given in a box. Use appropriate words to fill up the blanks in the following statements. [Air, oxygen, wind, water vapour, mixture, combination, direction, road, bottles, cylinders] (a) The __ makes the windmill rotate. (b) Air is a of some gases. (c) A weathercock shows the in which the air is moving at that place. (d) Mountaineers carry oxygen _ with them while climbing high mountains.

(a) Wind Wind can be described as the movement of air from the high-pressure area to the low-pressure area. There are many types of wind such as... View Article

Make sentences using the given set of words. (a) 99%, oxygen, nitrogen, air, together (b) Respiration, dissolved, animals, air, aquatic (c) Air, wind, motion, called

(a) Oxygen and Nitrogen together make 99% of air. Oxygen is one of the major components of air around us. Air comprises almost 21% oxygen. When... View Article

In a number of musical instruments, air plays an important role. Can you name such instruments?

Air plays an important role in a number of musical instruments such as trumpet, mouth organ, flute, etc. In ancient times, the air was thought... View Article

State whether the following statements are true or false. If false, correct them. (a) Plants consume oxygen for respiration. (b) Plants produce oxygen during the process of making their own food. (c) Air helps in the movements of sailing yachts and gliders but plays no role in the flight of birds and aeroplanes. (d) Air does not occupy any space.

(a) True During respiration, in different plant parts, significantly less exchange of gas takes place. Hence, each part nourishes and fulfils its... View Article

Usha took a lump of dry soil in a glass and added water to it till it was completely immersed. She observed bubbles coming out. The bubbles contain (a) water vapour (b) only oxygen gas (c) air (d) none of these.

C) Air On pouring water in the lump of soil, air is released in the form of bubbles. A lump of dry soil contains trapped air. When the water is... View Article

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