• 3 months ago
Transcript
00:00Hi kids! Today we will learn about our most important friend, air. So let's start!
00:09Air. Our Earth is surrounded by air, which we call as our atmosphere.
00:18This layer extends up to many kilometers above the surface of the Earth.
00:25All living things need air to live.
00:29As all animals breathe in oxygen, which they get from air.
00:35All plants breathe in carbon dioxide, which too they get from air.
00:42So there can be no life without air.
00:47Kids, can you tell how much air is there in this room?
00:53No, because air has no fixed volume.
01:00Now, can you tell what is the shape of air in this room?
01:05No, air has no fixed shape, but it takes the shape of its container, like water.
01:14But it takes the shape of its container, like water.
01:18Let's see an example.
01:22Here is a balloon. Now let's fill it with air.
01:28Now this balloon has air.
01:32What is the shape of the air in the balloon?
01:37Air has the same shape as that of the balloon.
01:41Now let's see if the air has some weight.
01:45Let's see.
01:48First of all, weigh an empty balloon.
01:53Now weigh the same filled balloon.
01:57You will find that the filled balloon has more weight than the empty one.
02:03So we can say that the air has some weight or mass.
02:09Here are some things that shows that the air takes up space.
02:14Balloon, tube, tires, bubbles.
02:20All these things are inflated because of air in them.
02:24It shows that air occupies space.
02:28Have you seen air or felt air?
02:31Let's see some things that makes us feel the air.
02:36When we switch on the fan.
02:40When a hair dryer is switched on.
02:43When you see a kite flying in the air.
02:47A parachute in the air.
02:50A wind wheel.
02:53All these examples shows us the presence of air.
02:57Kids, air is present just everywhere.
03:02Let's see how we can prove it.
03:06Here is an empty glass bottle.
03:09Is there anything inside it?
03:12No, you will say it's an empty bottle.
03:17Let's see, is it really empty or not?
03:21Turn it upside down.
03:23And now dip the mouth of the bottle into the bucket.
03:28It is filled with water.
03:31Does the water enter the bottle?
03:34No, water is not entering the bottle.
03:38We are required to apply a lot of force to keep it upside down.
03:44Now tilt the bottle slightly.
03:47What do you observe?
03:50A bubbly sound or some bubbles coming out of it.
03:57It shows that some air was there in the bottle which came out.
04:03And when the air came out, only then the water enters the bottle.
04:09So water filled up the empty space that the air had occupied in the bottle.
04:17This activity shows that air occupies space and air is present everywhere.
04:25In every empty thing, there is actually some air.
04:30It's not empty.
04:32Now let's see what is air made up of.
04:36Air is a mixture of gases, nitrogen, oxygen, carbon dioxide, some rare gases, dust particles, and water vapors.
04:5178% is nitrogen, 21% oxygen, and 1% includes carbon dioxide, some rare gases, water vapors, and dust particles.
05:08Now let's see some uses of air and how air is important for us.
05:15Moving air, that is the wind, has great force.
05:20It enables the movement of sailboats and gliders.
05:25It runs windmills which are used to generate electricity.
05:30Wind also helps in the dispersal of seeds.
05:35Air supports combustion.
05:38That is, combustion or burning is possible because of air and more precisely oxygen in the air.
05:48If there is no oxygen, there can be no combustion.
05:53Let's see an activity to prove it.
05:57Take a burning candle and now invert a glass over it and observe what happens.
06:06After some time, the candle will go off on its own.
06:12How did it happen or why did it happen so?
06:17It is because the combustion uses oxygen in the air and when all oxygen is used from the air in the glass,
06:25the combustion stops by its own as there is no oxygen left in the glass.
06:35So kids, there can be no combustion without oxygen which is present in the air.
06:44And we need combustion for just so many purposes.
06:49We need combustion to cook many types of food.
06:53We need combustion to generate heat.
06:57We need combustion to produce electricity in thermal power plants.
07:03We need combustion to run many industries and even run vehicles
07:10as engines of vehicles too run with the help of combustion of fuel in them.
07:17Even for hairstyling, we use hair dryers to dry and style our hair.
07:25Air is used to keep us warm too.
07:29Woolen clothes are worn because there is air trapped in small places in the woolen fabric.
07:37So kids, today we learned a lot about air and we should do our best to keep it clean and fresh.
07:46Now you may go ahead and take a quiz to learn more.
07:50Bye-bye.