Transcript the atmosphere - St Kevins College

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
Gases in the atmosphere
Other
1%
Oxygen
21%
Nitrogen
Oxygen
Other
Nitrogen
78%
The Earth’s Atmosphere
The Earth’s Atmosphere
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 troposphere
The troposphere
Life on earth would
not survive without
the atmosphere
THE SUN
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:
1. The earth’s surface absorbs heat from
the sun. This heats the earths surface
2. The surface of the earth slowly lets
this heat out, which warms the air close
to the ground- RADIATION
3. The hot air rises because hot air is
lighter than cold air- CONVECTION
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
 JOURNEY OF EARTH AROUND THE SUN
homework
1. Draw a diagram of the earth with the
equator drawn in- pg 82, fig 12.2
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