Eli5: Using Boyle’s law to calculate volume in an oxygen tank

Question

I’m hoping someone can help me understand this concept.

So according to Boyle’s Law, pressure and volume are indirectly proportional
P1V1=P2V2

With that in mind when pressure goes up, volume goes down. Why does the opposite happen when you are decreasing pressure in an Oxygen tank?

I’m thinking it has to do with the release of the gas but is there a different formula that calculates the remaining volume when you are decreasing the PSI on the gauge?

Or am I using the equation incorrectly.

In: Physics

Answer 1

You are thinking of it incorrectly. Boyle’s law is best explain when using a cylinder as an example.

As you push on the rod of cylinder you are decreasing the volume in the cylinder and increasing the pressure because the gas is being compressed; when you pull the rod out you are increasing the volume and decreasing the pressure because you are decompressing the gas.

Edit: If you are asking because of SCUBA reason just remember the deeper you go under water the more pressure the water is applying to you thus the more you and your equipment are being compressed and this is why Boyle’s law applies here.