When you buy a container of ice cream, you may think that a quart is a quart until you learn that one brand contains a lot more air than another. You can weigh the two containers and you’ll know that the heavier one contains more product. The same is true for gases: two tanks may be “full” from the top to the bottom, but the volume of stored gas is based on density, which is mostly determined by pressure.
Like most common gases, oxygen expands to fill its container. But how much oxygen is actually inside? You may know that an oxygen cylinder contains some number of cubic feet of oxygen, but the cylinder doesn’t look like it could possibly hold that much. It’s the compressibility of oxygen that makes it possible to squeeze a mass of gas into a small space.
Continue reading How much oxygen do you need? (Part 1)