Chapter 2 Study Guide

Kinetic energy

The energy of an object in motion, specifically in the context of the atmosphere where electrified regions contain ions and free electrons.

Latent heat

The heat released or absorbed by a unit mass of a substance during a change of state, such as evaporation or condensation.

Conduction

The transfer of heat by molecular activity from one substance to another, always moving from warmer to cooler regions.

Convection

The motions in a fluid that result in the transport and mixing of the fluid’s properties, often associated with vertical movements of air.

Absolute zero

A temperature reading of 0 K, or -273 C°, where theoretically, there is no molecular motion.

Fahrenheit scale

A temperature scale where 32 F is the freezing point of water and 212 F is the boiling point of water at sea level.

Celsius scale

A temperature scale where 0 C is the freezing point of water and 100 C is the boiling point of water at sea level.

Kelvin scale

A temperature scale where 0 K is the theoretical temperature at which all molecular motion ceases, often called the absolute scale.

Greenhouse effect

The warming of Earth’s atmosphere through the absorption and emission of infrared radiation by gases while allowing shortwave radiation to pass.

Albedo

The percentage of radiation returning from a surface compared to that which strikes it; represents surface reflectivity.

Electromagnetic waves

Energy propagated in the form of waves that do not require molecules to propagate and travel at nearly the speed of light in a vacuum.

Specific heat

The amount of heat energy required to raise the temperature of one gram of a substance by one degree Celsius.

Thermals

Small rising parcels of warm air produced when the Earth's surface is heated unevenly.

Solar constant

The rate at which solar energy is received on a surface at the outer edge of the atmosphere when perpendicular to the sun's rays.

Blackbody

A hypothetical object that absorbs all radiation that strikes it and emits radiation at a maximum rate for its temperature.

Longwave radiation

Infrared energy emitted by Earth and the atmosphere, typically associated with lower energy states.

Shortwave radiation

Radiant energy emitted from the sun, primarily in the visible and near ultraviolet wavelengths.

Scattering

The process by which small particles in the atmosphere deflect radiation from its path into different directions.

Advection

The horizontal transfer of any atmospheric property by wind.

Visible region

Radiation with a wavelength between 0.4 and 0.7 m, which can be perceived by the human eye.

Latent heat of evaporation

The amount of energy required for a liquid to change into a gas.

Latent heat of condensation

The energy released when gas turns into a liquid, resulting in decreased molecular energy and slower speeds of gas molecules.

Winter solstice

The point in the Northern Hemisphere when the sun is lowest in the sky, typically occurring around December 21.

Summer solstice

The time in the year when the sun is highest in the sky, generally around June 21 in the Northern Hemisphere.

Vernal equinox

The equinox occurring around March 20, when the sun passes directly over the equator and begins to approach the Northern Hemisphere.

Autumnal equinox

The equinox occurring around September 23, when the sun passes over the equator toward the Southern Hemisphere.