1. The Atmosphere
Chapter 3
Section 2
Ms. Cuthrell
Ecology
1st Period

2. The Atmosphere Mixture of gases surrounding the Earth.
Parts of this mixture:
Nitrogen
Oxygen
Carbon Dioxide
Other

3. The Atmosphere
Gases are constantly being added and taken away from the atmosphere.
How?
Animals
Plants
Volcanoes
Cars

4. The Atmosphere Insulates the Earth’s surface.
Slows the rate at which the Earth’s surface loses heat.
Keeps Earth at a temperature where individuals can survive.

5. Atmosphere Composition
Nitrogen = 78%
Enters when volcanoes erupt, dead plants and animals decay.
Oxygen = 21%
Primarily produced by plants.
Other gases = 1%
Argon, carbon dioxide, methane, and water vapor.

6. Atmosphere Composition
Contains many solid particles or atmosphere dust.
Atmosphere dust: - mainly soil
Salt, ash from fires, volcanic ash, matter from combustion, skin, hair, bits of clothing, pollen, bacteria, and viruses.
Aerosols: tiny, liquid droplets.

7. Air Pressure The atmosphere is pulled toward the Earth by gravity.
This makes it so the atmosphere is denser at the Earth’s surface.
Almost entire mass of atmospheric gases are located 30 km from planet’s surface.
Fewer gas molecules above 30 km.
Higher elevation = lower density

8. High Elevation
Why do people who climb to the top of Mt. Everest have trouble breathing?

9. Layers of the Atmosphere
The Troposphere
The Stratosphere
The Mesosphere
The Thermosphere

10. Troposphere The troposphere is where all weather takes place.
It is the region of rising and falling packets of air.
The air pressure at the top of the troposphere is only 10% of that at sea level (0.1 atmospheres).
There is a thin buffer zone between the troposphere and the next layer called the tropopause.

11. Stratosphere Above the troposphere is the stratosphere.
Air flow is mostly horizontal.
The thin ozone layer in the upper stratosphere has a high concentration of ozone, a particularly reactive form of oxygen.

12. Ozone Layer
This layer is primarily responsible for absorbing the ultraviolet radiation from the Sun.
The formation of this layer is a delicate matter, since only when oxygen is produced in the atmosphere can an ozone layer form and prevent an intense flux of ultraviolet radiation from reaching the surface.
There is considerable recent concern that manmade flourocarbon compounds may be depleting the ozone layer, with dire future consequences for life on the Earth.

13. Mesophere
Above the stratosphere is the mesosphere and above that is the ionosphere (or thermosphere).
In the mesosphere temperature decreases with increasing height.
The upper boundary of the mesosphere is the mesopause, which can be the coldest naturally-occurring place on Earth with temperatures below 130 K

14. Thermosphere Also called the ionosphere.
This layer is in the upper atmosphere.
The gases of the thermosphere are increasingly thinner than in the mesosphere. As such, incoming high energy ultraviolet and x-ray radiation from the sun, absorbed by the molecules in this layer, causes a large temperature increase.
The temperature increases with height and can reach as high as 3,600°F (2,000°C) near the top of this layer;
However, despite the high temperature, this layer of the atmosphere would still feel very cold to our skin because of the extremely thin air.
The total amount of energy from the very few molecules in this layer is not enough to heat our skin.

15. Auroras

16. Auroras

17. Auroras

18. Layers Review

19. Energy in the Atmosphere
Radiation: transfer of energy across space in the atmosphere
Conduction: flow of heat from a warmer object to a colder object when placed in direct physical contact.
Convection: heat transfer by currents.