Our Atmosphere And Its Pollutants
Transcript
00:00Hi kids! Today we will learn how important is our atmosphere and what's
00:09polluting it. So let's start! Our earth is surrounded by a blanket of air called
00:18atmosphere. It is composed of a mixture of gases, dust particles, and water vapors.
00:30The atmosphere protects the earth and allows life on earth. The atmosphere
00:37contains 21% of oxygen that living things need for respiration.
00:46The atmosphere contains 0.03% carbon dioxide which all plants need for
00:54respiration. The solar radiations or solar energy passes through atmosphere
01:02before reaching the earth's surface. The solar radiations also contain harmful
01:10ultraviolet rays and these harmful ultraviolet rays are filtered out by the
01:17ozone layer which is a part of the atmosphere. And life on earth gets only
01:24the good part of the solar radiations. When the earth gets heated upon, getting
01:30the solar radiation, the earth's surface reflects off this energy into the space
01:36at nighttime. But gases like carbon dioxide absorbs these reflected
01:42radiations and prevents earth from becoming freezing cold by reflecting off
01:48all the solar radiations. And this is known as greenhouse effect. As if all the
01:57heat reflected back by the earth's surface is allowed to escape into the
02:02space, our earth will become too cold at night that life cannot survive. It is the
02:10atmosphere because of which optimum temperatures is maintained on earth for
02:16the life to exist on earth.
02:20So without atmosphere we would be burned by the intense heat of the Sun during
02:27the day or frozen by the very low temperatures at night.
02:34The atmosphere also shields the earth from collisions with meteors and other
02:41small heavenly bodies. As these small heavenly bodies burn in the sky before
02:48hitting the earth's surface, so atmosphere acts as our shield. Oxygen
02:57levels of 21% is maintained by the atmosphere which is just apt for the
03:04life to survive. The atmosphere plays an important role in water cycle too. Water,
03:12one of the most essential elements for living things, is present in the air.
03:18Water bodies underground and even on hilltops.
03:25And this water is in a mode of continuous movement on, above, or below
03:33the surface of the earth. And this movement of water is called water cycle.
03:39And this water cycle too is regulated with the help of our atmosphere. So kids,
03:47it's the atmosphere that provides necessary gases for living things to
03:52survive. And it's the atmosphere that regulates the heat from the Sun to just
03:58the right temperature on earth. And it's the atmosphere that plays a very
04:04important role in water cycle too. And it's the ozone layer of atmosphere that
04:11protects the living things from the harmful UV rays. Our atmosphere also
04:17protects us from heavenly bodies like meteors. In our solar system, only two
04:26planets other than Earth have atmospheres, and they are Venus and Mars.
04:34Kids, we learned how important our atmosphere is, but unfortunately we are
04:42polluting our atmosphere. Let's see what is air pollution. The
04:49wanted and harmful substances in the air is termed as air pollution.
04:57Any additional gases, particles, or odors that are introduced into the air can
05:04cause harm to the living things and can be termed as pollution. Pollutants. Things
05:14that pollute the air are called pollutants. Common examples of pollutants
05:20include nitrogen oxides, carbon monoxides, hydrocarbons, sulfur oxides, sand, dust
05:30particles, and organic compounds.
05:35Pollutants can be classified into two types. Primary pollutants, secondary
05:43pollutants. Primary pollutants are those gases or particles that are introduced
05:50into the air through activities like volcanoes, dust storms, smoke from forest
05:58fires, vehicles, thermal power plants. There are all gases like carbon monoxide,
06:08sulfur dioxide, and dust particles.
06:14Now let's see what are secondary pollutants. When primary pollutants in
06:19the air mix up, they form even more harmful substances in the air, which are
06:26called secondary pollutants. Smog is an example of secondary pollutants. Smog is
06:35a form when fog is mixed with smoke and a poisonous form of fog is formed which
06:42we call as smog. So kids, that's all for today. Today we learned what is atmosphere,
06:52what is the role of atmosphere, what is pollution, and various types of pollutants.
06:59Now you may go ahead and take a quiz to learn more. Bye-bye!