Seasons and Angle of Sunlight Feb 10 th
1.
What two factors create our changing seasons?
2.
What is our longest day of the year? Why?
3.
What is our shortest day of the year? Why?
4.
How would the answers to #2 and #3 compare if you lived in the Southern Hemisphere? (ex. Australia)
5.
Does the angle of light striking an object affect the amount of energy being received by the object?
Gases in the Atmosphere
•
Atmosphere

is the blanket of air and moisture that surrounds the earth
 it extends to about 500km, after 500km the vacuum of space begins.
•
The atmosphere consists of:
78% Nitrogen Gas N
2
21% Oxygen Gas O
2
1 % Other Gases CO
2
,H
2
O, O
3

The Atmosphere:
1. Troposphere

closest to the surface (8-16km)

contains most of the moisture and is responsible for most of our weather
2. Stratosphere

16-50km above sea level
• 
has the highest amount of ozone gas. Ozone (O3) helps protect the earth from harmful UV rays
Memorizing the Layers:
•
Troposphere
•
Stratosphere
•
Mesosphere
•
Thermosphere
•
Exosphere
Try
Some
Meat
Tomatoes
Everyday
Atmospheric Pressure
• 
Atmospheric pressure is the pressure that air exerts as gravity pulls it toward the centre of the earth
•  altitude is the height above sea level, usually measured in m or km
• 
as altitude increases atmospheric pressure decreases
• 
on a weather map low pressure areas are represented with the letter “L”, high pressure areas “H”
• 
Atmospheric pressure is measured in kilopascals (kPa) using a barometer .