Columbia Encyclopedia

Search results

500 results found

scale insect

(Encyclopedia)scale insect, common name for members of a highly modified group of insects belonging to several families of the superfamily Coccoidea. Scales possess antennae and are characterized by reduced legs. O...

scale, in cartography

(Encyclopedia)scale, in cartography, the ratio of the distance between two points on a map to the real distance between the two corresponding points portrayed. The scale may be expressed in three ways: numerically,...

thermostat

(Encyclopedia)thermostat, automatic device that regulates temperature in an enclosed area by controlling heating or refrigerating systems. It is commonly connected to one of these systems, turning it on or off in o...

melting point

(Encyclopedia)melting point, temperature at which a substance changes its state from solid to liquid. Under standard atmospheric pressure different pure crystalline solids will each melt at a different specific tem...

Richter scale

(Encyclopedia)Richter scale rĭkˈtər [key], measure of the magnitude of seismic waves from an earthquake. Devised in 1935 by the American seismologist Charles F. Richter (1900–1985) and technically known as the...

Fujita scale

(Encyclopedia)Fujita scale fo͞ojēˈtə, fo͞oˈjētə [key] or F-Scale, scale for rating the severity of tornadoes as a measure of the damage they cause, devised in 1951 by the Japanese-American meteorologist Tet...

degree-day

(Encyclopedia)degree-day, a unit of measure used to estimate the fuel and power requirements in heating and cooling a building; it is equal to a difference of 1 degree between the outdoor daily average temperature ...

grease

(Encyclopedia)grease, mixture of lubricant and thickener. It is used to reduce friction between surfaces from which oils would leak away or cause damage by dripping, or where lubrication must be assured for extende...
 

Browse by Subject