And what Charles Law does is it relates volume and temperature. Remember Boyle's Law related volume and pressure? Well, Charles Law relates temperature and volume when pressure is constant. And what it says is that volume is directly proportional to temperature. And this means if we bring the T over or if we multiply a constant by T and we bring T over, what we get is the following v divided by T is equal to a constant. Remember, in Boyle's Law we saw that P times V gave us a constant and that if we increase pressure, our volume must decrease while keeping the constant the same.