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bacteria

(Encyclopedia)bacteria [pl. of bacterium], microscopic unicellular prokaryotic organisms characterized by the lack of a membrane-bound nucleus and membrane-bound organelles. Once considered a part of the plant king...

ether, in chemistry

(Encyclopedia)CE5 Ethers ether, any of a number of organic compounds whose molecules contain two hydrocarbon groups joined by single bonds to an oxygen atom. The most common of these compounds is ethyl ether, C...

acetylene

(Encyclopedia)acetylene ĕthˈīn [key], HC≡CH, a colorless gas. It melts at −80.8℃ and boils at −84.0℃. Offensive odors often noted in commercial acetylene are due to impurities. Acetylene forms explosiv...

phosphoric acid

(Encyclopedia)phosphoric acid, any one of three chemical compounds made up of phosphorus, oxygen, and hydrogen (see acids and bases). The most common, orthophosphoric acid, H3PO4, is usually simply called phosphori...

refining

(Encyclopedia)refining, any of various processes for separating impurities from crude or semifinished materials. It includes the finer processes of metallurgy, the fractional distillation of petroleum into its comm...

septic tank

(Encyclopedia)septic tank, underground sedimentation tank in which sewage is retained for a short period while it is decomposed and purified by bacterial action. The organic matter in the sewage settles to the bott...

diffusion

(Encyclopedia)diffusion, in chemistry, the spontaneous migration of substances from regions where their concentration is high to regions where their concentration is low. Diffusion is important in many life process...

exobiology

(Encyclopedia)exobiology or astrobiology, search for extraterrestrial life within the solar system and throughout the universe. Philosophical speculation that there might be other worlds similar to ours dates back ...

adaptation

(Encyclopedia)adaptation, in biology, has several meanings. It can mean the adjustment of living matter to environmental conditions and to other living things either in an organism's lifetime (physiological adaptat...

compression

(Encyclopedia)compression, external stress applied to an object or substance, tending to cause a decrease in volume (see pressure). Gases can be compressed easily, solids and liquids to a very small degree if at al...