How much does1m3 of air weigh?

Answer 1

We can answer that, but the answer isn't simple. Try to stay with us here:

First of all, it depends on the temperature, pressure, and humidity of the air.

For dry air at a temperature of zero Celsius (32 Fahrenheit) and pressure of

760 mm Hg, the density is

1.2929 gram per liter = 1.2929 kilogram per m3 .

The weight of 1.2929 kilogram is 12.67 newtons (2.85 pounds). (rounded)

BUT . . . . .

Don't forget that anything surrounded by a fluid is buoyed up by a force equal to

the weight of the displaced volume of fluid. So our cubic meter of air is buoyed up

by a force equal to the weight of a cubic meter of air, and winds up weighing zero !

Surrounded by vacuum, it weighs about 2.85 pounds. But surrounded by more air,

it weighs exactly nothing.

Which is why every cubic meter of air in the room doesn't fall down on the floor.