How Does the Earth Receive Heat From the Sun?

By Steve Jones
Steve Jones

Steve Jones is an experienced mathematics and science teacher. He also has many years experience in the field of public speaking and debate, and he is an organizer of debate competitions for high school students. He is the chairman of the Hungarian branch of the English-Speaking Union, which is an international educational charity founded in 1918 to promote international understanding and friendship through the use of the English language.

www.marlixint.com

When heat comes to Earth from the sun, various forms of radiation are absorbed in the atmosphere and converted into infrared radiation. Discover why ultraviolet rays can be more dangerous than infrared rays with information from a science teacher in this free video on radiation and science lessons.

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Video transcription

Hi I'm Steve Jones and I'm going to tell you how the Earth receives heat from the sun. Well it doesn't receive heat directly. The space between the Earth and the sun of course is a vacuum. It doesn't contain any material so heat can't be conducted and you can't get any convection all you can get is radiation and coming from the sun are various kinds of radiation, ultra violet, infra red, visible, X-rays, radio waves. Of course all of these are electro-magnetic radiations. We say they are electro-magnetic radiations and light visible radiation, light, is just one of these electro-magnetic radiations. Now as these radiations impinge on the atmosphere above the Earth they can be absorbed by the atmosphere and having absorbed in the atmosphere then emits radiation as infra red. So when the X-rays for example come from the sun most of them don't get to us here on Earth because they are absorbed in upper layers of the atmosphere and are converged into other forms of radiation particularly infra red which means that the Earth warms up. So this is a very important thing because it protects us from the radiation which is dangerous. It also provides heat making the planet warmer than it would normally be. Infra red radiation does come directly from the sun but it is at a very low level and therefore we can't really significantly feel that radiation. Ultraviolet is another radiation which again is absorbed in the atmosphere. This is the radiation of course which gives us a nice sun tan or gives us sun burn if we are not careful but again that radiation can be absorbed in the atmosphere giving out infra red at a lower level. Infra red radiation is a lower energy radiation than any of these ultra violet, then even visible than X-rays. Lower energy than that of radio waves and radio waves have a very low level so that is basically how heat gets to us from the sun.