1. What is Weather? What is the atmosphere?
The condition of the Earth’s atmosphere at a particular time and place.
What is the atmosphere?
The envelope of gases that surround the planet.

2. What makes up our atmosphere?
There are four main gases that make up our atmosphere. They are Nitrogen, Oxygen, Carbon Dioxide and Water Vapor.
There is more Nitrogen in the air than oxygen.
Plants absorb Carbon Dioxide and produce Oxygen for us to breathe.

3. What is the ozone?
A form of oxygen that has three oxygen atoms in each molecule instead of the usual two.
Good ozone is found in the ozone layer. Bad ozone is found in smog (ozone close to the ground)

4. What is water vapor?
Water in the form of gas.

5. How do we live???
The Earth’s atmosphere makes conditions on Earth suitable for living things.
The atmosphere traps energy from the sun, which keeps most of the Earth’s surface warm enough for water to exist as a liquid
The atmosphere protects us from dangerous radiation from the sun.
The atmosphere protects us from being hit by meteoroids.

6. Pressure… Pressure is the force pushing on an area or surface.
If pressure is the force pushing on an area, what is air pressure?

7. Air Pressure…
Air pressure is the result of the weight of a column of air pushing down on an area. The column of air extends upward through the entire atmosphere.

8. What is Altitude??? Altitude is simply the distance above sea level.
Sea level is the average level of the surface of the oceans.

9. Air Pressure and Altitude Rule:
Air pressure decreases as altitude increases. As air pressure decreases, so does density.

10. Altitude and Density:
As you go up in the atmosphere, the density of the air decreases. This means that the higher up you go, the gas molecules that make up the atmosphere are farther apart at high altitudes.

11. Why would you be more out of breath running at the top of a mountain than on the beach?
There are less oxygen molecules at the top of the mountain than on the beach. As you go up in the atmosphere, there are less oxygen molecules.

12. Layers of the Atmosphere…

13. Troposphere… This is the layer that you live in!
The Troposphere is the layer that weather occurs in.
The conditions are always changing because weather is always changing.

14. The Stratosphere…
This is the second layer of the atmosphere where the ozone layer is located.
The ozone layer protects living things from dangerous ultraviolet radiation from the sun.

15. The Mesosphere…
Meso means middle so the mesosphere is the middle layer of the atmosphere.
This is the layer of the atmosphere that protects the Earth’s surface from being hit by most meteoroids.

16. The Thermosphere… The air in this layer is extremely hot!
The Ionosphere is located in the thermosphere
The ionosphere helps reflect radio waves.
The Aurora Borealis (Northern) Lights occur in the Ionosphere.
The Thermosphere…

17. The Exosphere
This is the layer of Earth’s atmosphere that extends into space. It has no definite outer limit but blends gradually with outer space.