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THE ATMOSPHERE. The atmosphere is the gases which surround the earth They have no odour or colour The atmosphere is made up of 78% Nitrogen 21% Oxygen 1% other gases. The Earth’s Atmosphere. The Earth’s Atmosphere. The atmosphere is important because.
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The atmosphere is the gases which surround the earth • They have no odour or colour • The atmosphere is made up of • 78% Nitrogen • 21% Oxygen • 1% other gases
The atmosphere is important because • It provides us with the air we breathe • It absorbs heat from the sun during the day • It keeps heat in at night • It protects us from harmful rays of the sun
The atmosphere • The atmosphere is made up of a few layers • Almost all clouds and water vapour are found in the layer of the atmosphere closest to the surface of the earth • This layer is called the TROPOSPHERE • This is the layer in which weather occurs
THE SUN • The sun is a huge star at the middle of the solar system • The heat from the sun is called solar energy • Solar energy provides heat and light to the atmosphere and to the surface of the earth
How the atmosphere is heated: • The earth’s surface absorbs heat from the sun. This heats the earths surface • The surface of the earth slowly lets this heat out, which warms the air close to the ground- RADIATION • The hot air rises because hot air is lighter than cold air- CONVECTION
The sun heats the earth unevenly • The temperature of a place depends on its position on the earth’s surface... Or the latitude of that place • Latitude is the distance north or south of the equator… who knows what the equator is?
Latitude • The equator an imaginary line drawn around the centre of the earth • It is at 0° latitude
Low latitudes… • Places near the equator are said to be in low latitudes, and are usually hot • The sun is almost directly above the equator all year, so its rays hit the surface from directly overhead • These rays cover little ground and so give a lot of heat
High latitudes… • Places far away from the equator are said to be in high latitudes, and are usually cold • At higher latitudes, far from the equator, the sun’s rays are slanted • This means they cover a lot of ground and so give little heat
homework • Draw a diagram of the earth with the equator drawn in- pg 82, fig 12.2 • Draw a diagram of how the earth’s surface is heated unequally by the sun- (pg 83, fig. 12.4), and explain this diagram