I asked my teacher, and I was told that volume is the independent variable, and that pressure is dependent. The textbook I'm using said the same thing. After looking up some graphs of the law, I found that both pressure and volume were used as independent variables. It seems counter-intuitive to me, that volume would be the independent variable. Does that mean that if I have two gasses, Gas A and Gas B (← lesser volume), that Gas B should be under greater pressure, because of it's lower volume? If pressure is measured as force in Newtons / unit of area, then why would volume matter, if we only care about the the 2D area in contact with the atmosphere? Unless, it is the surface area in contact with the environment that we care about for pressure, which would make sense. To me, having pressure be the independent variable makes much more intuitive sense, as a greater pressure should decrease the volume. Thanks for any help.