1. Air Pressure Ch. 15

2. Air Pressure Review Air has mass. Air takes up space. Air has density. Air pressure is the weight of a column of air pressing down on an area.

3. Atmosphere/Pressure Atmosphere held in place by gravity Pressure strongest at surface-more air above you *as altitude increases, air pressure decreases –Stack of books –(Volleyball example)

4. Air Pressure As Air Pressure decreases, so does density.

5. Atmosphere Atmosphere: a mixture of gases that surrounds Earth: acts like a blanket –Contains oxygen –Protects from sun

6. Layers of the Atmosphere Troposphere-we live here, weather happens here Stratosphere: ozone layer Mesosphere: “middle layer” Thermosphere

7. Atmosphere

8. Composition of Troposphere Nitrogen=78%Oxygen=21% Other 1%=water vapor, CO2 and other

9. Weather Factors Sun’s energy travels to earth as Electromagnetic waves.

10. Weather Factors Scattering: Reflections of light in all directions. Why is the sky blue?

11. Radiation Sun on your face standing by campfire standing by campfire direct transfer of energy by electromagnetic waves through space.

12. Conduction Bare feet burned by hot sand direct transfer of heat from one substance to another through direct contact.

13. Convection Basement colder than upstairs transfer of heat by the movement of fluid or air. Hot air rises, cold air sinks.

14. Examples Cooking on the stove-pot on burner Hot air balloon rising Fireplace warming a room Curling iron on hair Blow dryer on hair Air from furnace heating the house

15. How is Earth heated? Light/heat from the sun RADIATES through the atmosphere, hits the Earth where it is absorbed. This heats the air above it by CONDUCTION. This heat rises up to the greenhouse gases where it is trapped, cools, sinks and heats at the surface again.- CONVECTION.

16. Weather Factors

17. Greenhouse Effect These gases absorb the heat and act as a “blanket” to keep Earth warm. Some greenhouse gases: water, methane, carbon dioxide.

18. Runaway Greenhouse Effect

20. http://www.epa.gov/climatechange/kids/glo bal_warming_version2.html

21. Define and Design Draw, color, label and explain your own picture of the Greenhouse Effect.

22. Egg in bottle Fire warmed up air inside, molecules escaped before egg was put on top and when egg wobbled. When fire went out, temperature cooled, molecules condensed, changing air pressure. Since the pressure outside bottle was higher, the higher pressure tried to get in the bottle. Since the egg is squeezable, it got pushed into the bottle by the air.