When the effects of compressibility on the solution are small, the aerodynamicist may choose to assume that density is constant.

When the density is allowed to vary, the problem is called a compressible problem.

When P and N-doped layers are placed in contact, diffusion ensures that electrons flow from high to low density areas: That is, from the N to the P side.

When the upper layer cooled so its density was greater than the lower layer, the waters mixed ( 1978 – 79 ).

When the process of escape and return reaches an equilibrium, the vapor is said to be " saturated ," and no further change in either vapor pressure and density or liquid temperature will occur.

When there is less than total information about the state of a quantum system we need density matrices to represent the state.

When a piece of lithosphere that was heated and stretched cools again, its density rises, causing isostatic subsidence.

When used to characterise protein folding, it measures the conformation by determining the overall size of a monolayer of the protein and its density in real time at sub-Angstrom resolution.

When a photographic film is exposed to light, the result of the exposure can be represented on a graph showing log of exposure on the horizontal axis, and density, or log of transmittance, on the vertical axis.

When the density of mass in the FLRW metric is set to zero ( an empty ' Milne universe '), then the cosmological coordinate system used to write this metric becomes a non-inertial coordinate system in the flat Minkowski spacetime of special relativity, one where surfaces of constant time-coordinate appear as hyperbolas when drawn in a Minkowski diagram from the perspective of an inertial frame of reference.

When the density of the solution is properly calibrated, the hematite will sink and the silicate mineral fragments will float and can be removed.

When the mass density of this central body exceeds a particular limit, it triggers a gravitational collapse which, if it occurs with spherical symmetry, produces what is known as a Schwarzschild black hole.

When a fluid element is displaced on an interface or internally to a region with a different density, gravity tries to restore the parcel toward equilibrium resulting in an oscillation about the equilibrium state or wave orbit.

When the interface between these two surfaces is not horizontal and the system is close to hydrostatic equilibrium, the gradient of the pressure is vertical but the gradient of the density is not.

When the denominator is the sum of the person-time of the at risk population, it is also known as the incidence density rate or person-time incidence rate.

When embryonic ectodermal cells are cultured at low density in the absence of mesodermal cells they undergo neural differentiation ( express neural genes ), suggesting that neural differentiation is the default fate of ectodermal cells.

When both parameters are less than one ( α < 1 and β < 1 ), this is the anti-mode: the lowest point of the probability density curve.

When defining what is meant by a compressible flow, it is useful to compare the density to a reference value, such as the stagnation density,, which is the density of the fluid if it were to be slowed down isentropically to stationary.

When a knife-edge is used, the system is generally referred to as a schlieren system, which measures the first derivative of density in the direction of the knife-edge.

When DNA is extracted from these cells and centrifuged on a salt density gradient, the DNA separates out at the point at which its density equals that of the salt solution.

When the Hall Probe is held so that the magnetic field lines are passing at right angles through the sensor of the probe, the meter gives a reading of the value of magnetic flux density ( B ).

When values of temperature derived with this instrument were compared with the accepted values associated with liquid helium-4 vapor pressures, differences of about 10 and 7 millidegrees respectively were found.

When the temperature reached 32-degrees-F all protozoan activity ceased ; ;

When this water level has been reached, inject steam into the wheel until the temperature reaches that shown in Column B of Table 2.

When this water level has been reached, inject steam until the temperature is that shown in Column Aj.

When this water level has been reached inject steam until the temperature is that shown in Column Aj.

When the pressure applied on a parcel of air decreases, the air in the parcel is allowed to expand ; as the volume increases, the temperature falls and internal energy decreases.

When compressed at room temperature to 7 GPa, α-berkelium transforms to the beta modification, which has a face-centered cubic ( fcc ) symmetry and space group Fmm.

When the working liquid is water and the bain-marie is used at sea level, the maximum temperature of the material in the lower container will not exceed 100 degrees Celsius ( 212 F ), the boiling point of water at sea level.

When the partial pressure of is reduced, for example when a can of soda is opened, the equilibrium for each of the forms of carbonate ( carbonate, bicarbonate, carbon dioxide, and carbonic acid ) shifts until the concentration of in the solution is equal to the solubility of CO < sub > 2 </ sub > at that temperature and pressure.

When the temperature is low, the spring winds and closes the valve, which allows the fan to spin at about 20 % to 30 % of the shaft speed.

When a small increment of heat is gained by a calorimetric body, with small increments, of its volume, and of its temperature, the increment of heat,, gained by the body of calorimetric material, is given by

When the temperature decreases again, the rock contracts, causing pieces of the rock to break off.

When the moisture content evaporates during detonation, cooling occurs, which reduces the temperature of reaction.

When a system, for example, n moles of a gas of volume V at pressure p and temperature T, is created or brought to its present state from absolute zero, energy must be supplied equal to its internal energy U plus pV, where pV is the work done in pushing against the ambient ( atmospheric ) pressure.

When the temperature rises beyond a certain point, called the Curie temperature, there is a second-order phase transition and the system can no longer maintain a spontaneous magnetization, although it still responds paramagnetically to an external field.

" When Groucho himself was on his deathbed, and a nurse came around with a thermometer, explaining that she wanted to see if he had a temperature, he responded, " Don't be silly — everybody has a temperature.

When heat is added to a thermal system, the change in entropy is the increase in mass-energy divided by temperature:

When this insulation is insufficient to maintain body temperature, they may resort to shivering -- rapid muscle contractions that quickly use up ATP, thus stimulating cellular metabolism to replace it and consequently produce more heat.

When the blade of an ice skate passes over the ice, the ice undergoes two kinds of changes in its physical state and a change in temperature due to kinetic friction and the heat of melting.

When the temperature drops below 50 ° F ( 10 ° C ), feeding, particularly with protein, is halted or the food can spoil in their stomachs, causing sickness.

When temperature is changed one of the phases grows, forming different morphologies depending on the temperature change.