1. Atmosphere Notes

2. What are the properties of air? Mass – air consists of atoms and molecules. Mass – air consists of atoms and molecules. Density – the amount of mass in a given volume of air. Density – the amount of mass in a given volume of air. Pressure – the force pushing on an area or surface. Pressure – the force pushing on an area or surface.

3. What is the atmosphere? The layer of gases that surround the planet. The layer of gases that surround the planet. Earth’s atmosphere makes conditions on Earth suitable for living things. Earth’s atmosphere makes conditions on Earth suitable for living things.

4. Composition? 78% nitrogen, 21% oxygen, and 1% argon and other gases.

5. What’s in the other 1% ?  Argon gas  “Greenhouse Gases” like… carbon dioxide carbon dioxide water vapor methane and more

6. Atmospheric Pressure Air pressure is greater near the Earth’s surface. This is because there are more molecules in the air near the Earth’s surface than at the top of the atmosphere. Air pressure is greater near the Earth’s surface. This is because there are more molecules in the air near the Earth’s surface than at the top of the atmosphere. As you move up from sea level, air pressure decreases because there is less density of particles. As you move up from sea level, air pressure decreases because there is less density of particles.

7. Atmospheric Pressure Heated Air – Less Dense and exerts a lower pressure Heated Air – Less Dense and exerts a lower pressure Colder Air – Higher density of molecules and exerts a higher pressure. Colder Air – Higher density of molecules and exerts a higher pressure.

8. What is a barometer? A barometer is the instrument we use to measure air pressure. A barometer is the instrument we use to measure air pressure. Read pages 510-511, fill in definitions on your notes. Read pages 510-511, fill in definitions on your notes.

9. Air pressure and altitude Altitude is your height above sea level. Altitude is your height above sea level. Higher altitude=low pressure Higher altitude=low pressure Lower altitude=higher pressure Lower altitude=higher pressure That’s why it’s colder higher in the troposphere (bottom layer). Mount Charleston, Nevada

11. Troposphere Layer of the atmosphere closest to the Earth's surface Layer of the atmosphere closest to the Earth's surface Tropo means “turning” or “changing”. Tropo means “turning” or “changing”. It contains 75% of the atmosphere's mass It contains 75% of the atmosphere's mass Temperature and pressure decrease as you go higher up the troposphere Temperature and pressure decrease as you go higher up the troposphere Where weather occurs Where weather occurs 0-12 km

12. Stratosphere Layer directly above the troposphere Layer directly above the troposphere Strato means “layer” or “spreading out”. Strato means “layer” or “spreading out”. Lower portion of the stratosphere has the ozone layer. Lower portion of the stratosphere has the ozone layer. This temperature increase with altitude is the opposite of the situation in the troposphere This temperature increase with altitude is the opposite of the situation in the troposphere Airplanes travel here Airplanes travel here 12-50 km

13. Ozone Layer The ozone layer protects us from ultraviolet radiation. The ozone layer protects us from ultraviolet radiation. The ozone layer absorbs most of the sun’s UV radiation before they reach us. The ozone layer absorbs most of the sun’s UV radiation before they reach us. As the radiation is absorbed, the earth’s atmosphere heats up. As the radiation is absorbed, the earth’s atmosphere heats up.

14. Ozone is good in the upper atmosphere, but it is NOT good to breathe. OXYGEN OZONE

15. Scientists study the ozone layer.

16. One group of gases is particularly damaging to the ozone layer. These gases are called CFCs, (Chloro-Fluoro-Carbons). CFCs destroy ozone molecules. Most countries have started using different substances in place of CFCs and the whole in the ozone layer is shrinking.

17. Mesosphere cold layer of the atmosphere, directly above the stratosphere cold layer of the atmosphere, directly above the stratosphere Meso means “middle” Meso means “middle” temperature generally decreases with increasing altitude temperature generally decreases with increasing altitude Meteors burn up in this layer Meteors burn up in this layer 50-80 km

18. Thermosphere temperature is hot and may be as high as thousands of degrees temperature is hot and may be as high as thousands of degrees Thermo means “heat” Thermo means “heat” Very few molecules in this layer Very few molecules in this layer Divided into the Ionosphere and the Exosphere. Divided into the Ionosphere and the Exosphere. 80 km and up

19. Ionosphere This layer contains ions (electrically charged particles. This layer contains ions (electrically charged particles. Auroras occur here because particles from the sun enter the ionosphere near the poles and they strike the nitrogen and oxygen making them electrically charged. This causes the molecules to glow. Auroras occur here because particles from the sun enter the ionosphere near the poles and they strike the nitrogen and oxygen making them electrically charged. This causes the molecules to glow. 80 – 550 km

20. Exosphere Exo means “outer” Exo means “outer” Satellites & the space station orbit here Satellites & the space station orbit here This layer does not have a distinct end, but instead just merges into outer space. This layer does not have a distinct end, but instead just merges into outer space. 550 km and up