Earth's Atmosphere

Questions

1. How big is the atmosphere?
2. What is the composition of the atmosphere?
3. What does the atmosphere do?
4. How does energy and specifically heat move around in our atmosphere?
5. What is albedo?
6. What effect does the angle of the sun's rays have on the heating of the planet?

Lecture Notes

• Lecture Notes
• Powerpoint Slides
• Powerpoint Slides (large)

News Articles

• Weather balloon GPS space flight iPhone camera footage homemade spacecraft
• In a Takeout Container, a Trek to the Stratosphere

Background Information

• The Atmosphere (Wikipedia)
• Structure and Composition of the Atmosphere (video)
• The Origin of Oxygen in Earth's Atmosphere
• Aspen Global Change Institute: Structure of the atmosphere
• Layers of the Atmosphere
• The Jet Stream
• It's Elemental: Nitrogen

Demonstrations

Preparation of oxygen by decomposition of hydrogen peroxide catalyzed by manganese oxide using downward displacement of water.

Comparison of the ability of three gases: oxygen, nitrogen and air to support the combustion of a candle flame

Lava lamp as an illustration of convection: Hot material rises, cools and sinks in a repeating cycle.

Infrared Camera. Learn About Infrared

Albedo.We observed that the thermometer in the black pocket heated up higher than the thermometer in the white pocket. Read more...

Take Away (Main) Points

1. The air is mostly (78%) composed of nitrogen, a chemically unreactive gas.
2. The atmosphere is divided into layers: troposphere, stratosphere, mesosphere and thermosphere with different temperature profiles. Most of the mass of the air is in the first layer - the troposphere - where weather occurs.
3. The ozone layer is in the stratosphere where is filters (blocks it from reaching the Earth's surface) ultraviolet radiation from the sun.
4. Heat is a form of energy caused by moving molecules and atoms. Matter exists in three phases: solid, liquid, gas. The gas phase has the highest energy (fastest moving particles) and the solid phase has the lowest energy (slowest moving particles)
5. The poles of the planet are cooler than the equatorial region due to the angle of incidence of the incoming sunlight which affects its intensity and the amount of atmosphere the sunlight must traverse.
6. The Earth is heated from the ground up - higher frequencies are absorbed by the planet and emitted as infrared radiation. We experience infrared radiation as heat.
7. Heat is transferred in three ways: conduction (direct contact), convection (circulation of fluids and gases), and radiation (pure energy travelling through space).
8. The albedo (reflectivity) of a surface determines what percentage of incident radiation is absorbed or reflected (bounced off).
9. The total average mass of the atmosphere is about 5x10¹⁸ kg, 5 billion billion kilograms