rarefactions
Zones of expansion
Rarefactions are regions where pressure or density decreases, the opposite of compressions.
In physics, sound waves consist of alternating compressions and rarefactions—areas where air molecules bunch together and spread apart.
The term applies wherever a medium becomes less dense: the rarefactions in a longitudinal wave, atmospheric rarefactions at high altitude.
Forcing into smaller space
- soundAudible wave phenomenon
- propagationAct of spreading widely
- mediumMiddle size or state
- longitudinalAlong the longer dimension
amplitude · frequency · oscillation · vibration · pulse · wavelength · periodic · interference
Enlargement of an opening
- stretchingExtending muscles or material
- distensionEnlargement from pressure
- thinningReducing density or number
- spreadingExtending over space
dispersion · diffusion · dilation · decompression · spacing · separation · divergence · scattering
Instrument gauging atmospheric pressure
- altimeterInstrument measuring elevation
- aneroidWithout liquid medium
- hypobaricBelow-normal atmospheric pressure
- troposphereLowest atmospheric layer
stratosphere · mesosphere · thermosphere · exosphere · meteorology · weather · altitude · density
Quantified chaos in systems
- enthalpyThermodynamic total heat quantity
- isothermalAt uniform temperature
- reversibleAble to be undone
- cyclicRepeating in sequence
equilibrium · heat · work · energy · compression · expansion · gas · ideal
compression
Forcing into smaller space
- soundAudible wave phenomenon
- propagationAct of spreading widely
- mediumMiddle size or state
longitudinal · amplitude · frequency · oscillation · vibration · pulse · wavelength · periodic · interference · diffraction
dilatation
Enlargement of an opening
- stretchingExtending muscles or material
- distensionEnlargement from pressure
- thinningReducing density or number
spreading · dispersion · diffusion · dilation · decompression · spacing · separation · divergence · scattering · dissipation
barometer
Instrument gauging atmospheric pressure
- altimeterInstrument measuring elevation
- aneroidWithout liquid medium
- hypobaricBelow-normal atmospheric pressure
troposphere · stratosphere · mesosphere · thermosphere · exosphere · meteorology · weather · altitude · density · thinning
entropy
Quantified chaos in systems
- enthalpyThermodynamic total heat quantity
- isothermalAt uniform temperature
- reversibleAble to be undone
cyclic · equilibrium · heat · work · energy · compression · expansion · gas · ideal · Boyle
rarefactionscompressions
Acts of pressing together
condensations · contractions · compactions · concentrations · consolidations