It depends upon your state law, but 100 feet would be a general answer.
It affects sky divers because the closer you are to the ground the faster you go.
Boyle's Law, Charles's Law, and Archimedes principle are the main principles. Study those and that should get you started.
scuba diving.
Charles's Law states: At constant pressure, the volume of a given mass of an ideal gas increases or decreases by the same factor as its temperature (in Kelvin) increases or decreases. Volume /temperature = K (constant) Boyle's Law states: Boyle's law states that at constant temperature, the absolute pressure and the volume of a gas are inversely proportional. Pressure Volume= K (constant) It can also be stated this way: Forcing the volume V of a fixed quantity of gas to increase, while keeping the gas at the initially measured temperature, the pressure P must decrease proportionally. Conversely, reducing the volume of the gas increases the pressure. These are gas Laws Scuba divers must know.
Jacques Charles invented the Charles' Law.
Charles law: T.v=kBoyle law: p.v=k
Gases obey Charles' Law, so T1V2 = T2V1: that is, as temperature increases, so does volume, as temperature decreases, so does volume... so long as the pressure is adjusted or allowed to be constant.For more, check out Charles' Law.
Charles B. Law was born in 1872.
Charles B. Law died in 1929.
when your changing you might want to know...
There are no legal requirements to scuba dive. In other words, anyone can scuba dive without breaking a law (assuming you are not doing an illegal underwater activity such as illegal fishing). However, if you are not certified, you will not be able to rent or buy equipment or get someone to fill your scuba cylinder.