Understanding Earth's Atmosphere: Composition, Layers, and Effects

2. Do Now 1. What is the atmosphere? 2.What are the main gases that compose the atmosphere?

3. What is the Atmosphere? All of the gases that surround Earth  Mixture of mostly nitrogen and oxygen  Other gases that are present in trace amounts (small amounts) include argon, carbon dioxide, methane and water vapor

4. Composition of the Atmosphere • Nitrogen 78% • Oxygen 21% • Other 1% • Argon, • Carbon Dioxide • Methane • Water Vapor

5. The Composition of Gases in the Atmosphere is constantly changing! • Think of any examples of gases being added or removed in the atmosphere

7. What Else is in the Atmosphere? In addition to gases, the atmosphere also contains some particulates. We call these particles atmospheric dust. • What are some materials that might be part of atmospheric dust?

8. What Else is in the Atmosphere? • Volcanic ash • Aerosols • Bacteria • Soil particles • Pollen • Fire ash • Combustion ash

9. Gravity The force that pulls everything to the earth! • Gravity causes the Earths atmosphere to be MORE dense near the Earth’s surface!So at higher elevations, the air becomes LESS dense!

10. Think…Denver, CO is a mile high city. If you were to ski in the Denver area, you might have a hard time breathing. Why?Write down your ideas

11. Denver, CO is a mile high city. If you were to ski in the Denver area, you might have a hard time breathing because… 1. You’re exercising and need more oxygen 2. However, the air is less dense which means it has less oxygen!

12. Think…Why do planes fly at higher altitudes where the air is less dense?Write down your

13. Planes fly at higher altitudes where the air is less dense because…At lower densities, there is less drag and therefore higher fuel effeciency.

14. Gravity How does gravity affect the layering of the atmosphere? Denser materials are closer to the earth. Denser layers of the atmosphere will be closer to the earth.

15. Layers of the atmosphere?

16. Troposphere • Nearest to Earth’s surface • About 18 km high • Densest layer • Within this layer temperature decreases as altitude increases

17. Stratosphere • Above Troposphere • 18 km to 50 km • Contains ozone layer • Ozone* molecules absorb UV energy from the sun and heat up this layer • Therefore, temperature Increases as altitude increases *Ozone O3 reduce UV radiation that reaches the Earth

18. Mesosphere • Above the Stratosphere • 50 km to 80 km high • Coldest layer • Temperature decreases as altitude increases

19. Thermosphere • Farthest from Earths surface • 80km-550 km • N2 and O2 absorb solar radiation • Temperatures of 2000 C • Molecules in this layer absorb harmful x-rays and gamma rays from the sun, causing atoms to become electrically charged ions • Also called the ionization layer • Aurora borealis- Solar lights

20. AURORA BOREALIS

21. Directions • Individual work on the atmosphere worksheets. • Match the terms from Column B with Column A. • Use the key to label the ozone layer, and each layer of the atmosphere. - You can go on a lab table or work at your desk.

24. Interpret this Graph • What happens as to the temperature as you rise through the… -Troposphere? -Stratosphere? -Mesosphere? -Thermosphere?

25. What layer includes the Ozone layer?  The Stratosphere Ozone* is a molecule made of three oxygen atoms it can be found near the ground where its bad, or up in atmosphere where its good…hence, good up high, bad nearby *Ozone O3 reduce UV radiation that reaches the Earth

26. What does the ozone layer do?

27. What does the ozone layer do? • The ozone layer absorbs UV radiation from the Sun. • UV radiation is part of the electromagnetic spectrum. • Exposure to UV radiation can lead to skin cancer

28. So…Why is a hole in the ozone layer or ozone depletion bad???

29. So…Why is a hole in the ozone layer or ozone depletion bad??? • Too much UV radiation might cause skin cancers

30. Energy in the Atmosphere Primary source of energy is THE SUN! • Solar energy reaches the Earth as electromagnetic radiation. Only a small amount reaches the Earths surface. • The rest is either reflected or absorbed. What do these terms mean? • What numbers represent reflection? Absorption?

31. Energy Transfer in the Atmosphere There are three important mechanisms that transfer heat into the atmosphere: • Radiation- Transfer of energy across space and in the atmosphere (ex. heat felt standing in front of a fire) • Conduction- flow of heat from a warmer object to a colder one when in direct physical contact • Convection- transfer of heat by air currents. Hot air rises, cold air sinks. (ex. heat felt if you hold your hand above a stove)

33. The Movement of Air Around the Earth • Weather • Most weather occurs in the Troposphere, where temperatures decrease as altitude increases. • So, less dense air warmed by the Earth’s surface rises, then as the currents rise, they cool, become dense, and sink. • A continual process of warm air rising and cool air sinking in a circular motion- Convection Currents!

34. Convection Currents in the Atmosphere Think… • Where else were convection currents?

35. Weather vs. Climate Climate  Average weather of some place over a long period of time

36. The Greenhouse Effect Process in which gases trap heat neat the Earth and without which the Earth would be too cold for life to exist

37. Global Climate Regulation Air currents move energy around and regulate global climate

38. Let’s Wrap Up the Atmosphere! • Atmosphere video clip