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Edu-Primes
  • 9/21/2024
Transcript
00:00Earth is the third planet from the sun. You probably already know a lot about the planet
00:08Earth, because Earth is the planet where we live. Although it is the largest of the inner
00:15planets, or the four rocky planets that orbit nearest the sun, the earth is far, far smaller
00:22than the four gas giants that circle the outer edges of the solar system. The earth is also
00:29the first planet when traveling out from the sun to have a moon, and the only planet in
00:35the solar system to have only one moon.
00:41The earth is unique among the planets of the solar system, because earth is the only planet
00:47that has liquid water on its surface. Other planets are either too hot, causing all their
00:54water to evaporate into gases, or too cold, causing any water they have to freeze into
01:00ice. The earth is about 93 million miles or 150 million kilometers away from the sun,
01:11which keeps it at just the right temperature to have liquid water. And the earth has a
01:17lot of water. More than 70% of the earth's surface is covered by oceans. That means that
01:27the oceans are more than twice the size of all the land on earth. Because earth has so
01:34much water on it, it is sometimes called the blue planet.
01:41Liquid water is what allows life to exist on earth. As far as we know, earth is the
01:48only place that life exists. Millions of species of plants and animals call the planet earth
01:55home, including humans.
02:00Earth's atmosphere is another important feature. The atmosphere is a thick layer of gases that
02:07covers the entire earth. It is mostly made of nitrogen and oxygen. The atmosphere is
02:16what allows us to breathe. It also helps keep the earth warm by acting like a blanket to
02:23hold in the sun's heat. Another way the atmosphere helps us is by protecting the earth from harmful
02:31radiation from the sun, and also from meteors. Anything falling to the earth from space
02:41is rubbed against the gases in the atmosphere until they burn. Most things burn up completely
02:47before they reach the surface, but even anything that makes it through is much smaller by the
02:53time it hits the ground.
02:57The earth goes around the sun. The time it takes to go around the sun is called a year.
03:06It takes the earth about 365 days to travel around the sun once. That is why a year is
03:13usually 365 days.
03:19The earth also rotates, or spins. The time it takes for the earth to rotate once is called
03:27a day. The earth rotates every 24 hours, and that is why a day is 24 hours long.
03:39The earth does not rotate straight up and down. It is tilted. There is an imaginary
03:45line through the earth from the north pole to the south pole, called the earth's axis,
03:52and this axis is tilted at about 23 degrees.
03:58Why is it important that the earth is tilted? Well, the tilt of the earth's axis is what
04:06causes the seasons. When a part of the earth is tilted towards the sun, it will be summer
04:13there. When it is tilted away from the sun, it will be winter instead.
04:21The inside of the earth is very different from the outside. If you were to cut the earth
04:27in half, you could see that it is made up of different layers. The outermost layer,
04:35called the crust, is where we live.
04:39The earth's crust is cool and solid. Everything you see, trees, mountains, rivers, houses,
04:51and even the oceans are sitting on top of the earth's crust. The crust is so thick
04:58that humans have never been able to dig deep enough to break through it, but the crust
05:03is only a thin layer on the surface of the earth.
05:09Underneath the crust is the mantle. The mantle is a thick layer of molten rock or magma.
05:18It is the thickest layer of the earth. Sometimes magma from the mantle will come up to the
05:24surface through volcanoes.
05:29The core is at the very center of the earth, and it is very, very hot, with a temperature
05:35of thousands of degrees. It is made of metal, mostly iron and nickel, and even though it
05:43is very hot, it is under so much pressure that it is solid.
05:50The earth is important to us because it is our home. About 7 billion people live on the
05:57earth right now, as well as millions of species of plants and animals. So far, we have not
06:05found any other planet in the entire universe that would make a good home for us, so it
06:10is important that we take care of the planet we have.
06:16I hope you enjoyed learning more about earth today. Goodbye till next time!