Characteristics of the Atmosphere

ATMOSPHERE is mixture of gases that surround the Earth.

• About 99% of the atmosphere is composed of nitrogen and oxygen.

• Nitrogen 78% and Oxygen 21%• The remaining one percent consisting of

small amounts of argon, hydrogen, carbon dioxide, water vapor, and other gases.

Earth’s Atmospheric Gases

AIR PRESSURE the measure of force with which air

molecules push on a surface. The gravitational attraction between Earth and

atmospheric gases causes particles of gas to be pulled toward the center of Earth.

Atmospheric pressure decreases with height because there are fewer and fewer gas particles exerting pressure.

Change in Air pressure is what causes your ears to “Pop”, when your ear drum tries to equalize the pressure in your ear.

As you move from the surface upwards ↑ the air pressure decreases with fewer air molecules above you. Sea level

pressure is 14.7 lbs per square inch

Layers of the Atmosphere The atmosphere is made up of several

different layers.

TROPOSPHERE

STRATOSPHERE

MESOSPHERE

TEROMOSPHERE

EXOSPHERE Each layer differs in composition and

temperature.

Air Temperature changes with height

Temperature changes with height

TROPOSPHERE

The layer closest to Earth’s surface, the densest layer contains 90% of the atmosphere gases, including water vapor.

All life is found in it. All weather takes place in the troposphere. As you go up in the Troposphere the

temperature and pressure DECREASES. Sfc to 10,000 km/ 71/2 mi. thick

STRATOSPHERE

– is where most ozone is located.

– Planes fly in the lower Stratosphere because there is no weather to jostle the planes.

– Temperature INCREASES with height due to the Ozone layer absorbing radiant heat from the Sun. Blocking most Ultraviolet energy.

– 10,000 to 50,000 km/ 7to 30 mi thick

MESOPHERE

is the coldest layer of the atmosphere. Temperature DECREASES with height. This is where you would see meteors

shooting through as they encounter more air molecules.

50,000 to 80,000 km/ 30 to 50 mi. thick

THERMOSPHERE– The upper most layer of the atmosphere

contains a very small part of the atmosphere’s mass mostly Nitrogen and Oxygen particles.

– This is the hottest layer because it is closer to the sun and it absorbs the heat from it.

– the IONOSPHERE which is made up of electrically charged particles is found in the Thermosphere where Auroras forms and radio waves bounce off it.

– TEMPERATURE INCREASES with height.

– 80,000 to 300,000 km/ 50 to 190 mi thick

Exosphere

– The exosphere, which is composed of light gases such as helium and hydrogen, so satellites can travel here very easily

– Molecules are actually traveling so fast that some are able to escape from earth’s gravity.

– There is no clear boundary between the atmosphere and space.