A Note to Parent Help your child identify different cloth materials available at home like bedsheets, silk sarees, blankets, curtains, gunny bags and so on. Let your child touch the material of each to understand the difference. Help him/ her to formulate a table like the one given below to note down his/her observations. Type of cloth material Features Our Need – Clothing 47
7Lesson Our Need – Air I Will Learn About • properties of air. • air for healthy living. • air pollution and ways to reduce air pollution in our surroundings. • some common diseases that spread through air. • ways to prevent diseases that spread through air. I Think Raghav saw a big balloon floating in the sky. His mother told him that it was a hot-air balloon. Raghav wants to know how it went so high in the sky. Do you know how? Hot-air balloon In Class 1 we learnt that air is all around us. But, we cannot see it; it has no colour and no smell. It flows around us. It fills up empty spaces. Let us learn more about air. Properties of air What happens when you fill a balloon with air? It gets bigger in size. This is because the air takes up the space inside the balloon. 48
When we blow more air, the balloon expands to fill more air inside it. So, the balloon gets bigger in size. Try this! Take two balloons and hang them at the two ends of a hanger. Observe the position of the hanger. Now, replace one of the balloons with a balloon full of air. What do you see? The hanger tilts towards the balloon that is filled with air. Can you guess the reason? The air inside the balloon makes it heavy. So, the hanger tilts towards that side. This shows that air has weight. Try this! Do this activity with the help of your teacher. Take a balloon and fix it on the mouth of a glass bottle. Now, place the bottle in hot water. What happens to the balloon? It gets filled with air. Where did that air come from? The bottle was already filled with air. When we The air has weight, keep it in hot water, the air inside the bottle also and it fills up space. gets heated. Heat makes the air expand, and it Air expands and becomes light in weight. So, it moves up into the moves upwards balloon. when heated. A hot air balloon moves up in the sky in a similar way. The air in the balloon is heated with a ? State two burner inside. When the air gets heated and properties of air. expands it becomes light in weight. So it moves up and carries the balloon up in the sky. Our Need − Air 49
Air for healthy living Do you go to a park to play or ride a Children riding bicycles bicycle? How do you feel there? You feel fresh and happy. Breathing in clean air makes us healthy and fresh. This is why people go for an early morning walk to parks and gardens. Breathing exercises help us to stay healthy and strong. Let us learn some of them. Try this! Lie on the floor. Place a small stuffed animal on your stomach. Breathe in. Feel the stuffed animal rise. Then breathe out from your mouth. Feel the stuffed animal going down. Stand straight. Droop your arms Breathing exercises in front of your body. As you breathe in, raise your arms up high. Breathe out and slowly swing your arms down. Air pollution and ways to reduce air pollution in our surroundings In Class 1, we have learnt that air filled with smoke and dust is bad for us. The presence of such harmful things like smoke and dust in the air is called air pollution. These things make the air dirty. Where do smoke and dust come from? When we burn something such as firewood or kerosene lamps, it gives out smoke. Burning of garbage also gives out a lot of smoke. Vehicles give out smoke and blow up dust in the air. All these make the air unclean. Any colour or bad smell of air shows that it is dirty. 50
People burst firecrackers (crackers) on festivals and special occasions. Do you think crackers are good for air? Crackers make the air unclean. They add smoke and burnt paper to the air. This air is not good for breathing. Firewood Kerosene lamp Vehicles Crackers We can reduce air pollution by using smoke-free lamps and stoves, stopping burning of garbage, taking care of our vehicles, planting trees and so on. Have you seen some people wearing masks even when there is no smoke or dust in the air? Why do they wear masks? The air around us carries germs. When we breathe air that has germs, we may fall sick. Let us learn about diseases that spread from one person to another through air. Some common diseases that spread through air When sick people breathe, cough or sneeze, germs from their mouth and nose spread in the air. When other people breathe in the same air, the germs may enter their body. Germs that cause diseases like common cold, chickenpox and measles spread in this way. How can we avoid the spread of germs A child suffering from through air? Let us see. chickenpox Ways to prevent diseases that spread through air • Use a handkerchief while sneezing or coughing. • Wear a mask in crowded places. Our Need − Air 51
• Do not spit in public places. • Keep the doors and windows of your house open to allow morning sunlight to come in. Sunlight can kill disease-causing germs. • Taking some medicines or injections also protects us from disease- causing germs. ? State two ways to keep away diseases that spread through air. A woman using A child wearing a handkerchief a mask Be Amaze A d We have a system inside our body which protects us against disease- causing germs. When the germs enter our body, this system attacks and kills those germs. It is like an army of soldiers that protect us from enemies! Connect the Dots English Fun Underline the nouns in the following sentences: 1) Air is all around us. 2) We should wear masks in crowded places. 52
Maths Fun You know that air gives shape to the things in which it is filled. Draw the different shapes of balloons that you might have seen. A Note to Parent Talk to your child about the precautions to be taken to keep Deep away air-borne diseases. Encourage him/her to do breathing breathing exercises daily for a healthy living. Demonstrate yogasanas and deep breathing to your child, and encourage him/her to do them on a daily basis. Vajrasana Dhanurasana Bhadrasana Shavasana Uttanasana Bhujangasana Yogasanas Our Need − Air 53
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