Atmosphere

auroras

a beautiful display of light in the sky that come from interactions between particles from the sun's atmosphere and gases in the ionosphere.

carbon dioxide

a colorless, odorless gas produced by burning carbon and organic compounds and by respiration. It is naturally present in air (about 0.03 percent) and is absorbed by plants in photosynthesis

oxygen

a colorless, odorless reactive gas, the chemical element of atomic number 8 and the life-supporting component of the air. Oxygen forms about 21 percent of the earth's atmosphere, and is the most abundant element in the earth's crust

conduction

a form of heat transfer where heat energy is directly transferred between molecules through molecular collisions or direct contact.

ionosphere

a sub-layer of the thermosphere containing ions.

exosphere

a sublayer of the thermosphere and the upper limit of the atmosphere where the atoms and molecules blend into space.

evaporation

a type of vaporization of a liquid that occurs from the surface of a liquid into a gaseous phase that is not saturated with the evaporating substance.

cloud

a visible mass of condensed water vapor floating in the atmosphere, typically high above the ground.

global warming

an increase in the average temperature of the earth's atmosphere, especially a sustained increase sufficient to cause climatic change.

barometer

an instrument used to measure air pressure.

greenhouse gases

gases such as carbon dioxide, methane, nitrous oxide, water vapor, and ozone in the atmosphere which are involved in the greenhouse effect.

ozone

is made up of three oxygen molecules and is what protects us from the sun's harmful UV radiation, which causes cancer, cataracts, and DNA mutation and harms plants and other animals on Earth.

radiation

is the transfer of energy through space by visible light, ultraviolet radiation, and other forms of electromagnetic waves.

precipitation

rain, snow, sleet, or hail that falls to the ground.

humidity

the amount of moisture in the air

relative humidity

the amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature.

dew point

the atmospheric temperature (varying according to pressure and humidity) below which water droplets begin to condense and dew can form.

condensation

the change in state from a gas to a liquid

argon

the chemical element of atomic number 18, an inert gaseous element of the noble gas group. Argon is the most common noble gas, making up nearly one percent of the earth's atmosphere.

nitrogen

the chemical element of atomic number 7, a colorless, odorless unreactive gas that forms about 78 percent of the earth's atmosphere.

temperature

the degree or intensity of heat present in a substance or object

atmosphere

the envelope of gases surrounding the earth or another planet.

air pressure

the force exerted by the weight of tiny particles of air (air molecules). At sea level the air pressure is 14.7 psi.

water vapor

the gas phase of water.

altitude

the height of an object or point in relation to sea level or ground level.

thermosphere

the layer of the atmosphere above the mesosphere where temperatures are the highest in the atmosphere. The increasing temperature is due to the strong influence of solar activity.

mesosphere

the layer of the atmosphere just above the stratosphere and below the thermosphere. It is the coldest part of the atmosphere and meteors burn up in this layer.

stratosphere

the layer of the atmosphere just above the troposphere and below the mesosphere. There is a temperature inversion due to the ozone layer which absorbs most of the sun's UV radiation.

troposphere

the layer of the atmosphere that is nearest to the Earth's surface. It is where most weather changes occur. It is the thinnest layer yet contains half of the Earth's atmosphere.

wind

the perceptible natural movement of the air, esp. in the form of a current of air blowing from a particular direction.

greenhouse effect

the phenomenon whereby the earth's atmosphere traps solar radiation, caused by the presence in the atmosphere of gases such as carbon dioxide, water vapor, and methane.

convection

the transfer of energy by which a substance, such as a gas or liquid, is heated and the warmer, less dense fluid rises, then cools and becomes more dense and thus sinks.