The troposphere is the lowest layer of Earth's atmosphere. Most of the mass (about 75-80%) of the atmosphere is in the troposphere. Most types of clouds are found in the troposphere, and almost all weather occurs within this layer. Air is warmest at the bottom of the troposphere near ground level. This air gets colder as one rises through the troposphere. That's why the peaks of tall mountains can be snow-covered even in the summertime. Air pressure and the density of the air also decrease with altitude. That's why the cabins of high-flying jet aircraft are pressurized. When you feel the wind on your face, see clouds in the sky, and watch a bird flap its wings in flight, you’re experiencing the troposphere. It’s a pretty nice layer to call home. Life on Earth would not be possible without a natural greenhouse effect. Without greenhouse gases, the Earth would be cooler and the average temperature would be freezing. Water vapour and carbon dioxide are the most important greenhouse gases. Water vapour makes up about 60% of the natural greenhouse effect, and carbon dioxide about 20%. Greenhouse gases trap heat emitted from the Earth and keep it close to the surface. The following image shows what controls the 'central heating' system of our planet. (1) The Sun is the source of all of the energy reaching the Earth. (2) Sunlight falls on all of the Earth's surface. (3) The Earth's surface does not take up all of the Sun's energy. Part of it is reflected directly back into space. Very light coloured surfaces (e.g. ice and snow) are excellent reflectors. (4) Some sunlight is reflected back into space by the top of clouds. (5) Gases and particles in the air take up (absorb) sunlight. (6) The surface of the Earth absorbs radiation from the Sun. This radiation is re-emitted as heat (long wave infrared radiation), warming the Earth. (7) A bit of the energy absorbed is required to make water evaporate. (8) A very small amount of the infrared radiation goes directly back into space. (9) Clouds not only reflect sunlight, they also absorb the heat radiation from the Earth. A cloudy sky keeps the Earth warm, like a blanket. (10) There are particles and gases in the air which absorb the infrared radiation emitted from the surface of the Earth. The gases are called greenhouse gases, because they trap the heat energy near the ground. If you look closely at the diagram you will notice that greenhouse gases are good, we need them to keep life in balance and survival is easy. Things get bad when we, as humans, add pollutants and create an imbalance...after the imbalance is started....what will happen next?
3 Comments
Errol
3/16/2018 01:55:10 pm
The mans face looked like it hurt and also the birds.....wouldn't it be weird to be swimming and then all these birds come across the water!
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Sadie
3/18/2018 12:24:24 pm
Good job on the blog!!!
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David
3/18/2018 01:16:19 pm
that big eye guy is freaky deaky. i hope everyone has had a good weekend and i hope everyone has a good rest of the day, bye
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Mrs. TaylorI love science! Everything about the world is interesting and never boring. I love to study plants, animals, insects, and people. My favorite subjects are my students who are the most unique organisms on the planet! Categories |