Weather

1. Weather Chapter 8

2. 8.1 Weather: Temperatures and Winds • Meteorologists are scientists who study the weather • By making observations, they can predict bad weather and keep people safe during dangerous storms • The Sun is the basic cause of all weather • The seasons, the winds, the clouds, the lightning, and the rain are all results of the sun’s influence

3. Weather: Temperatures and Winds • The atmosphere around the earth protects us from most of the sun’s radiation • Our atmosphere also traps heat and keeps the earth from becoming too cold • The atmosphere’s function of keeping heat from escaping into space is called the greenhouse effect • Most of the air that we live in receives its warmth “second-hand” from the ground • The ground reflects heat back up into the air and warms it

4. The Seasons • The earth takes about 365 days to complete one orbit around the sun • As it orbits the sun, the earth rotates on its axis • The axis is the earth’s center rotation point • The earth’s axis is actually tilted to the side • The seasons we experience on earth are a result of this tilted axis

5. The Earth’s Axis

6. The Seasons • The equator is an imaginary line that circles around the middle of the earth • The half of the earth above the equator is called the Northern Hemisphere • The Southern Hemisphere is the half of the earth below the equator • The seasons change around the world as the earth orbits the sun

7. The Equator and Earth’s Hemispheres

8. The Seasons • The two Hemispheres receive two opposite amounts of light as the earth moves • When people in the Northern Hemisphere experience summer, Southern Hemisphere residents experience winter • The differences between summer and winter temperatures in each hemisphere are caused by variations in the amount of solar radiations falling on the earth • Solar energy hits each hemisphere at a slant during that hemisphere’s winter months • Solar rays hit the hemispheres more directly during their season of summer

9. The Sun and Earth’s Seasons