1. The Atmosphere Why is there weather?
The Sun heats the surface of the Earth unequally
The Earth rotates
The atmosphere contains water vapour

2. Unequal heating is caused by the Earth’s shape
Equatorial latitudes receive more energy than Polar, and are thus warmer
The Earth’s atmosphere attempts to equalize the temperature around the globe by carrying warm air north and cold air south, and mixing them together
This is how temperatures would look if there were no continents or oceans

3. Seasons & heating (p. 508)
the Earth’s tilt changes the amount of sunshine received through the seasons
in June the northern hemisphere is tipped toward the sun, in December, away from the sun
The Earth’s rotation is elliptical (unlike this picture) so we are closest to the sun in December

4. The Atmosphere
The atmosphere is a blanket of air and moisture that surrounds the Earth
78% Nitrogen
21% Oxygen
1% Other gases
Altitude is the distance above sea level

5. Troposphere Closest to the surface
Up to 16 km at the equator and 8 km at the poles
Most of the moisture of the atmosphere is in this layer
Responsible for most of the weather systems
As you go further away from the earth (increase in altitude), this layer gets colder

6. Tropopause Thin boundary where the troposphere ends
No longer a decrease in temperature as the altitude increases
More ozone here to absorb UV radiation so the temperature increases
The heat created by the radiation helps to keep the troposphere separate from the stratosphere

7. Stratosphere This layer is very dry
Here there is a higher concentration of ozone than any other layer
Because of the high concentration of ozone, this layer does the most to protect the earth from radiation
As the altitude increases in this layer, the temperature also increases

8. Mesosphere
The temperature and density of the gases here are extremely low
Except for water vapour concentration and ozone, the composition of the atmosphere up to and including this layer are very similar
Shooting stars burn in this layer

9. Thermosphere
Low density but high energy molecules produce high temperatures
High energy waves from the sun are absorbed here
Also called the inosphere because radiation causes particles to become electrically charged Ions
The ions produce beautiful lights called auroras (Northern/Southern Lights)

10. Exosphere Thin, outermost layer
It can be considered space because there are so few particles present here (not very dense).

11. Pressure Higher altitude is harder to breathe:
Air is less dense
Fewer Oxygen molecules
Valleys have higher pressure because there is more weight on top of it
The temperature is usually higher so the air is less dense

12. Layers of the Atmosphere
The atmosphere is thicker above the equator because the air is warmer so it expands