Earth Science Final

What gases comprise Earth's present atmosphere?

Nitrogen 78%, Oxygen 21%, Argon 0.9%

How do we know air is matter and takes up space?

Air is made of matter because it has mass and takes up space (you can feel wind pressure, inflate a balloon)

How does the volume and density of air change as temperature changes?

As temperature increases, air volume increases and density decreases.

What is air pressure and how does it help us know air exists?

Air pressure is the weight of the atmosphere pushing down on a surface — it helps us know air exists because it can be measured with a barometer and felt (e.g., ear-popping on a plane)

Troposphere

lowest layer, where weather occurs, temperature decreases with altitude. Energy comes from Earth's surface radiating heat upward.

Stratosphere

contains the ozone layer, temperature increases with altitude because ozone absorbs UV radiation

Mesosphere

temperature decreases with altitude; meteors burn up here. Air is so thin it does not absorb radiation

Thermosphere

temperature increases dramatically with altitude; absorbs high-energy X-rays and UV; where auroras occur.

What happens to pressure with increasing altitude?

Pressure decreases with altitude because there is less air (fewer air molecules) above you pushing down.

Pressure on a graph

The relationship is shown on a pressure vs. altitude graph as a curve that drops steeply at first then levels off.

What causes convection and how does temperature effect it?

Uneven heating causes some air to warm more than surrounding air. Warm air is less dense and rises; cool air is more dense and sinks. Creates convection Currents

Energy absorbtion/reflection

30% of incoming rays are reflected/scattered. 20% is absorbed by atmosphere/clouds.

Why does energy increase/decrease in different layers.

Layers that absorb the most rays will increase in temp and layers that do not absorb will have cooler temps

What electromagnetic waves reach Earth’s surface

Radio Waves, Microwaves, Visible light, Infrared, Ultraviolet

Terrestrial Radiation

Infrared energy emitted by Earth’s surface after absorbing solar energy.