Columbia Encyclopedia

Search results

500 results found

atomic mass

(Encyclopedia)atomic mass, the mass of a single atom, usually expressed in atomic mass units (amu). Most of the mass of an atom is concentrated in the protons and neutrons contained in the nucleus. Each proton or n...

mass number

(Encyclopedia)mass number, often represented by the symbol A, the total number of nucleons (neutrons and protons) in the nucleus of an atom. All atoms of a chemical element have the same atomic number (number of pr...

mass production

(Encyclopedia)mass production: see production. ...

mass spectrograph

(Encyclopedia)mass spectrograph, device used to separate electrically charged particles according to their masses; a form of the instrument known as a mass spectrometer is often used to measure the masses of isotop...

alkaline dry cell

(Encyclopedia)alkaline dry cell: see battery, electric. ...

cyclone

(Encyclopedia)cyclone, atmospheric pressure distribution in which there is a low central pressure relative to the surrounding pressure. The resulting pressure gradient, combined with the Coriolis effect, causes air...

compressed air

(Encyclopedia)compressed air, air whose volume has been decreased by the application of pressure. Air is compressed by various devices, including the simple hand pump and the reciprocating, rotary, centrifugal, and...

air transportation

(Encyclopedia)air transportation: see aviation. ...

lock, air

(Encyclopedia)lock, air: see air lock.

liquid air

(Encyclopedia)liquid air, ordinary air that has been liquefied by compression and cooling to extremely low temperatures (see liquefaction). Its commercial preparation involves purification by washing to remove solu...