layers of the atmosphere

what is the % of the air that is oxygen?

21%

ozone

This is a form of oxygen that is high in the atmosphere. It shields living things from much of the harmful radiation given off by the sun.

atmosphere

This is a mixture of gases that surrounds Earth. In addition to containing the oxygen you need to breathe, it protects you from the sun's damaging rays and is always changing.

troposphere

This is the atmospheric layer that is closest to the Earth's surface. It is the layer in which we live. It is the densest atmospheric layer and contains 90% of the atmosphere's total mass. Almost all of the Earth's carbon dioxide, water vapor, clouds, air pollution, weather, and life-forms are in this layer.

air pressure

This is the measure of the force with which air molecules push on a surface. It is strongest at the Earth's surface because more air is above you. As you move farther away from the Earth's surface, fewer gas molecules are above you. So, as altitude (distance from sea level) increases, this decreases.

mesosphere

This is the middle layer of the atmosphere. It is also the coldest layer.

greenhouse effect

This is the process by which gases in the atmosphere, such as water vapor and carbon dioxide, absorb thermal energy and radiate it back to Earth. This process is given its name because the gases function like the glass walls and the roof of a greenhouse, which allow solar energy to enter but prevent thermal energy from escaping.

stratosphere

This is the second atmospheric layer. Gases in here are layered and do not mix as much as the layer closest to the Earth. The air is thin in this layer and contains little moisture. This layer contains the ozone layer.

thermosphere

This is the upper atmospheric layer. In this layer temperature increases with altitude. The temperatures in this layer can reach 1,000 degrees Celsius (around 1,800 degrees Fahrenheit). Even though the temperature is very high in this layer, it doesn't feel very hot. Weird, huh? Why?

air has pressure because...

air has mass

what instrument is used to measure air pressure

barometer

why is earths atmosphere important to other living things

it provides all the gasses that the livings need to survive

what layer protects earth from meteoroids

mesosphere

the layers of the atmosphere are classified by...

temperature

explain what happens to air molecules and air pressure as you climb a mountain

they both decrease