THE ATMOSPHERE

THE ATMOSPHERETHE ATMOSPHERE

The atmosphere is the gases which The atmosphere is the gases which surround the earthsurround the earth

They have no odour or colourThey have no odour or colour The atmosphere is made up ofThe atmosphere is made up of

– 78% Nitrogen78% Nitrogen– 21% Oxygen21% Oxygen– 1% other gases1% other gases

Gases in the atmosphere

Nitrogen78%

Oxygen21%

Other1%

Nitrogen

Oxygen

Other

The Earth’s AtmosphereThe Earth’s Atmosphere

The Earth’s AtmosphereThe Earth’s Atmosphere

The atmosphere is important The atmosphere is important becausebecause

It provides us with the air we breatheIt provides us with the air we breathe It absorbs heat from the sun during It absorbs heat from the sun during

the daythe day It keeps heat in at nightIt keeps heat in at night It protects us from harmful rays of the It protects us from harmful rays of the

sunsun

The atmosphereThe atmosphere The atmosphere is made up of a few The atmosphere is made up of a few

layerslayers Almost all clouds and water vapour are Almost all clouds and water vapour are

found in the layer of the atmosphere found in the layer of the atmosphere closest to the surface of the earthclosest to the surface of the earth

This layer is called the This layer is called the TROPOSPHERETROPOSPHERE This is the layer in which weather occursThis is the layer in which weather occurs

The troposphereThe troposphere

The troposphereThe troposphere

Life on earth would Life on earth would not survive without not survive without the atmospherethe atmosphere

THE SUNTHE SUN

THE SUNTHE SUN The sun is a huge star at the middle of The sun is a huge star at the middle of

the solar systemthe solar system The heat from the sun is called The heat from the sun is called solar solar

energyenergy Solar energy provides heat and light to Solar energy provides heat and light to

the atmosphere and to the surface of the atmosphere and to the surface of the earththe earth

How the atmosphere is How the atmosphere is heated:heated:

1.1. The earth’s surface The earth’s surface absorbs absorbs heat from heat from the sun. This heats the earths surfacethe sun. This heats the earths surface

2.2. The surface of the earth slowly lets this The surface of the earth slowly lets this heat out, which warms the air close to heat out, which warms the air close to the ground- the ground- RADIATIONRADIATION

3.3. The hot air rises because hot air is The hot air rises because hot air is lighter than cold air- lighter than cold air- CONVECTIONCONVECTION

Convection Convection

The sun heats the earth unevenlyThe sun heats the earth unevenly

The temperature of a place depends on The temperature of a place depends on its position on the earth’s surface... Or its position on the earth’s surface... Or the the latitudelatitude of that place of that place

LatitudeLatitude is the distance north or south is the distance north or south of the equator… who knows what the of the equator… who knows what the equator is?equator is?

LatitudeLatitude

The equator an imaginary line drawn The equator an imaginary line drawn around the centre of the eartharound the centre of the earth

It is at 0It is at 0° latitude° latitude

Low latitudes…Low latitudes… Places near the equator are said to be Places near the equator are said to be

in in low latitudeslow latitudes, and are usually , and are usually hothot

The sun is almost directly above the The sun is almost directly above the equator all year, so its rays hit the equator all year, so its rays hit the surface from directly overheadsurface from directly overhead

These rays cover little ground and so These rays cover little ground and so give a lot of heatgive a lot of heat

High latitudes…High latitudes… Places far away from the equator are Places far away from the equator are

said to be in said to be in high latitudeshigh latitudes, and are , and are usually usually coldcold

At higher latitudes, far from the At higher latitudes, far from the equator, the sun’s rays are slantedequator, the sun’s rays are slanted

This means they cover a lot of ground This means they cover a lot of ground and so give little heatand so give little heat

JOURNEY OF EARTH AROUND THE SUNJOURNEY OF EARTH AROUND THE SUN

homeworkhomework

1.1. Draw a diagram of the earth with the Draw a diagram of the earth with the equator drawn in- pg 82, fig 12.2equator drawn in- pg 82, fig 12.2

2.2. Draw a diagram of how the earth’s surface Draw a diagram of how the earth’s surface is heated unequally by the sun- (pg 83, fig. is heated unequally by the sun- (pg 83, fig. 12.4), and explain this diagram12.4), and explain this diagram