The phrase "air expands" is correct and usable in written English.
It can be used in contexts discussing physics, thermodynamics, or general discussions about gases and their behavior under different conditions.
Example: "As the temperature increases, air expands, causing the balloon to inflate."
Alternatives: "air increases in volume" or "air enlarges."
"Air expands at higher altitudes, the gas in our intestines expands too, up to 30percentt more than usual and that air needs to go somewhere," he says.
The poor chap will scream the whole flight as the air expands on ascent then can't get out.
The air expands violently away from this sudden increase in temperature, resulting in a shockwave we hear as thunder.
Then the air expands outward, shedding its energy at the speed of sound — the blast wave that destroys houses, hospitals, schools, cities.
The volume ratio of fuel to air established by the throat and fuel-jet sizes will be maintained with increased flow, but the weight ratio of fuel to air increases because the air expands to a lower density as the throat pressure decreases.
It consists of a cylinder in which heated air expands to drive a piston.
As the pilot ascends, therefore, air expanding in the sinuses must escape the body so that there is equal pressure inside and outside the body.
Could this be like supersonic jet planes that, when in the hangar, tended to leaked oil, but when in the air, expanded to have perfect skin for speed?
Cheap flights, he says, would get the millions of Mexican-Americans who go back and forth across the border out of their buses and into the air, expanding the market closer to 30m.But it is not just the gringos who have big ambitions for Mexico's low-fare market.
Barometric readings have a predictable behaviour to them that sees a sharp fall when the Sun comes over the crater every Martian sol (day) to heat the column of air, expanding it upwards and off to the sides.
A few companies may be bold enough to give consumers a break from ads, as Philips did when it bought all the commercial time on the NBC Nightly News but ran only three spots, totaling 75 seconds instead of the usual seven minutes, so the network could air expanded news segments.
