What does fluidized mean?
Fluidized means converted into a fluid-like state: a solid — usually a bed of fine particles such as sand, powder, or catalyst granules — has been transformed so that it flows, mixes, and behaves much like a liquid. This is typically achieved by forcing a gas, most often air, upward through the particles at a velocity that lifts and suspends them, so the whole mass expands, churns, and takes on the properties of a dense fluid. The term belongs mainly to chemical engineering, where the phrase 'fluidized bed' describes reactors, combustors, dryers, and coating systems built on this principle. Fluidization is prized industrially because it produces intimate contact between solids and gases, excellent heat transfer, and continuous, controllable flow of otherwise awkward powdery materials. Outside engineering, the concept appears in popular science demonstrations, where aerated sand famously behaves like quicksand. The word carries a technical, precise connotation rather than an everyday one, and in British usage it is often spelled 'fluidised.'
verb (past tense and past participle of 'fluidize')Converted into a fluid-like state, typically by blowing a gas upward through a bed of fine solid particles so that they behave like a liquid; more generally, made to flow or behave as a fluid.
- (Chemical engineering) To render a bed of fine solid particles fluid-like by passing a gas or liquid upward through it, so the particles suspend and flow like a fluid.
- (More generally) To make something behave as or resemble a fluid.
"The sand in the reactor was fluidized by a stream of pressurized air, allowing it to mix and flow like a liquid."
"Coal is fluidized in the combustor so that it burns more efficiently at lower temperatures."
"In the demonstration, air pumped through the tank fluidized the sand until a ball floated on its surface."
Fluidize sand and it will overflow like water, let objects float in it — and yes, it's the science behind some famous quicksand-style pool stunts.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fluidized
The word derives from 'fluid,' which entered English from Latin 'fluidus' ('flowing'), a derivative of 'fluere' ('to flow'), related to the root behind 'fluent' and 'influx.' The specific term 'fluidize' arose in twentieth-century chemical engineering, when fluidized-bed processes were developed for catalytic cracking of petroleum in the 1940s, and 'fluidized' is its regular past participle. Its cognates include 'fluidity' and 'fluidic,' all sharing the same flowing-root origin.
Related word forms
How fluidized is actually used
A technical term used chiefly in chemical engineering and industrial processing; rarely encountered outside those fields except in popular-science contexts. The verb is most commonly met in its past participle form within the phrase 'fluidized bed.' British usage often spells it 'fluidised' with an s rather than a z.
Easily confused with fluidized
'Fluidised' is simply the British spelling of the same word (with an s instead of a z), not a different word — both describe solids given fluid-like properties.