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Glossary of Terms > C


A unit equal to the kilocalorie (kcal) used to express the heat output of an organism and the fuel or energy value of food.


The measure of electrical charge stored within a capacitor.


Any of a group of organic compounds that includes sugars, starches and celluloses and serves as a major energy source in the diet of animals.


The electrode or terminal by which current leaves an electrolytic cell, voltaic cell, battery, etc.


The scale used to measure temperature where water freezes at zero and boils at one hundred degrees. Supersedes the Centigrade scale.


In Biology: The basic structural unit of all organisms containing nuclear and cytoplasmic material enclosed by a semipermeable membrane and, in plants, a cell wall. In Physics: A device which generates electrical energy from chemical energy. Several cells together form a battery.


Superseded by the celcius scale for mesasuring temperature. No longer used in schools.


The intensity of a distinctive hue. The saturation of a colour.


The physical unit of genetic material in a cell. The human species has 23 pairs, designated 1 to 22 in order of decreasing size and X and Y for the female and male sex chromosomes respectively.

Circuit (electrical)

The complete path of an electric current, including the power supply, connecting wires and components.

Colored gel

A stage term for coloured filters used in spotlights. Traditionally made from gelatin, nowadays from polycarbonate or polyester. Used to colour light beams.


A body that orbits the sun.


Having a curved surface like the inner surface of a sphere.

Conductivity (electrical)

The measurement of the ability of a material to conduct electricity.

Conductivity (thermal)

The measurement of the ability of a material to conduct heat.


a form of heat transfer which occurs in liquids and gases caused by changes in density due to the movement of particles.


Having a surface that is curved or rounded outward.


Abbreviation for Cathode Ray Tube, a glass envelope containing an electron gun. The electrons are deflected and strike a fluorescent screen. Older TVs contain CRT tubes.