15.1 Earth's Atmosphere
What is the ozone hole?
- a decrease in the ozone layer over Antarctica that happens each year from August through December - thought to be caused by CFCs
What is the ionosphere?
- a layer of electrically charged particles within the mesosphere and thermosphere(in between them) - where radio waves travel across country. (we use satellites more often now)
What are CFCs?
- chlorofluorocarbons are chemicals that destroy (by combining with . . .. )ozone - reducing the amount of ozone means more UV radiation reaches Earth's surface
the troposphere
- closest to Earth - contains 99% of the water vapor & 75% of the gases in the atmosphere - extends from Earth's surface to 10km above the surface - rain, snow, and clouds occur there
the thermosphere
- directly above the mesosphere - extends from 85km to 500km above the surface - has very high temperatures
the mesosphere
- directly above the stratosphere - extends from 50km to 85 km above the surface - where you might see a meteor
the exosphere
- directly above the thermosphere - has hardly any molecules - where the space shuttle orbits
the stratosphere
- directly above the troposphere - extends from 10km to 50km above the surface - part of the stratosphere contains the ozone layer
Why is atmospheric pressure high closer to the Earth's surface?
- gravity pulls the gases toward the surface - the molecules nearer the surface are closer together, making the air denser - denser air puts more force on the surface
the ozone layer
- it's located in the stratosphere - extends from 19 to 49km above the surface - ozone is made of 3 oxygen atoms per molecule - absorbs harmful ultraviolet (UV) radiation from the Sun (protect the earth from UV)
Name the 3 upper layers of the atmosphere
- mesosphere - thermosphere - exosphere
Why do different layers of the atmosphere have different temperatures?
- some layers have gases that can easily absorb the Sun's energy, and other gases do not
the temperature in the thermosphere and exosphere
- temperatures are very high(hottest two layers) - although there are few molecules, each one has a great deal of energy
How is the troposphere warmed?
- the Sun warms the Earth's surface, and the heat from the surface warms the air in the troposphere - as you go higher in the troposphere, the temperature DECREASES
How does temperature vary in the mesosphere?
- the higher you go in the mesosphere, the temperature DECREASES
How is the stratosphere warmed?
- the ozone absorbs some of the Sun's energy - as you go higher in the stratosphere, the temperature INCREASES is in the upper parts because the ozone
What is atmospheric pressure?
-the force of the atmospheric gases pressing down on the Earth below
What is the purpose of Earth's atmosphere?
1. maintains a balance between heat absorbed from the Sun and heat that escapes back into space 2. protects life forms from some of the Sun's harmful rays
the 5 layers of Earth's atmosphere
1. troposphere 2. stratosphere 3. mesosphere 4. thermosphere 5. exosphere
What causes smog?
Chemical pollutants mixed with oxygen and other chemicals in the presence of sunlight form a brown haze called smog
True or False: the higher you go in the atmosphere, the higher the atmospheric pressure.
False. The higher you go, the pressure decreases because the air is less dense.
Why is the amount of carbon dioxide in the atmosphere increasing?
Fossil fuels burned for energy release carbon dioxide into the atmosphere
What gases are in the atmosphere?
Nitrogen - 78% Oxygen - 21% Water vapor - 4% Argon and carbon dioxide - small amounts
True or False: the concentration of CFCs in the atmosphere has started to decrease.
True; many governments have banned their use
Earth's Atmosphere
a thin layer of air that forms a protective covering around the planet
What liquids are in the atmosphere?
droplets of liquids other than water example: droplets from erupting volcanoes
What solids are in the atmosphere?
dust, salt, and pollen
What is Earth's atmosphere made of?
gases, solids, and liquids