Physics Unit 2 Thermal Physics and Kinetic Theory (Definations)

Kinetic Theory of Matter

States that all matter is composed of particles in a continuous state of random motion.

Brownian Motion

The continuous, random, haphazard motion of microscopic particles suspended in a fluid, caused by collisions with fluid molecules.

Temperature

A measure of the degree of hotness or coldness of a body, or a measure of the average kinetic energy of its particles.

Fixed Points

Distinct, reproducible temperatures used to define a temperature scale, such as the ice point and the steam point.

Ice Point

The temperature of pure melting ice at standard atmospheric pressure, defined as 0 degrees Celsius.

Steam Point

The temperature of steam above pure boiling water at standard atmospheric pressure, defined as 100 degrees Celsius.

Clinical Thermometer

A specialized thermometer with a narrow range, a constriction in the bore, and a thin glass bulb used to measure human body temperature.

Boyle's Law

For a fixed mass of gas at constant temperature, the pressure is inversely proportional to its volume.

Charles's Law

For a fixed mass of gas at constant pressure, the volume is directly proportional to its absolute temperature.

Pressure Law

For a fixed mass of gas at constant volume, the pressure is directly proportional to its absolute temperature.

Absolute Zero

The temperature at which the particles of a gas have minimum kinetic energy, defined as 0 Kelvin or minus 273 degrees Celsius.

Heat Capacity

The quantity of thermal energy required to raise the temperature of a body by one Kelvin.

Specific Heat Capacity

The quantity of thermal energy required to raise the temperature of one kilogram of a substance by one Kelvin.

Latent Heat

The thermal energy absorbed or released during a change of phase at constant temperature.

Specific Latent Heat of Fusion

The quantity of thermal energy required to change one kilogram of a substance from solid to liquid without a change in temperature.

Specific Latent Heat of Vaporization

The quantity of thermal energy required to change one kilogram of a substance from liquid to gas without a change in temperature.

Conduction

The transfer of thermal energy through a material by molecular vibrations and free electron movement, without bulk movement of the material.

Convection

The transfer of thermal energy through a fluid by the actual bulk movement of the fluid itself, caused by changes in density.

Radiation

The transfer of thermal energy by means of electromagnetic waves, which does not require a material medium.

Good Emitters and Absorbers

Matt, black surfaces which absorb and radiate thermal energy highly efficiently.

Good Reflectors

Shiny, silver surfaces which reflect thermal radiation efficiently and are poor emitters and absorbers.

Greenhouse Effect

The process where atmospheric gases trap long-wavelength infrared radiation emitted by the Earth, warming the planet.