Columbia Encyclopedia

Search results

500 results found

Earth Day

(Encyclopedia)Earth Day, Apr. 22, a day to celebrate the environment. The first Earth Day was organized in 1970 to promote the ideas of ecology, encourage respect for life on earth, and highlight growing concern ov...

day

(Encyclopedia)day, period of time for the earth to rotate once on its axis. The ordinary day, or solar day, is measured relative to the sun, being the time between successive passages of the sun over a stationary o...

snowball earth

(Encyclopedia)snowball earth, hypothesized condition in which the earth was covered completely by ice during several periods in the Proterozoic. The hypothesis was originally developed to explain evidence of the co...

diatomaceous earth

(Encyclopedia)diatomaceous earth: see diatom.

earth goddess

(Encyclopedia)earth goddess: see Great Mother Goddess. ...

earth pig

(Encyclopedia)earth pig: see aardvark.

Earth Summit

(Encyclopedia)Earth Summit: see United Nations Conference on Environment and Development. ...

fuller's earth

(Encyclopedia)fuller's earth, mineral substance characterized by the property of absorbing basic colors and removing them from oils. It is composed mainly of alumina, silica, iron oxides, lime, magnesia, and water,...

black earth

(Encyclopedia)black earth: see chernozem.

rammed earth

(Encyclopedia)rammed earth, material consisting chiefly of soil of sufficiently stiff consistency that has been placed in forms and pounded down. It has been used for buildings and walls since ancient times and was...