Understanding air density and its effects
By Jack Williams, USATODAY.com
In simple terms, density is the mass of anything – including air – divided by the volume it occupies.
In the metric system, which scientists use, we usually measure density in terms of kilograms per cubic meter.
The air’s density depends on its temperature, its pressure and how much water vapor is in the air. We’ll talk about dry air first, which means we’ll be concerned only with temperature and pressure.
In addition to a basic discussion of air density, we will also describe the effects of lower air density – such as caused by going to high altitudes – on humans, how humidity affects air density – you might be surprised – and the affects of air density of aircraft, baseballs, and even racing cars.