Scuba diving fundamentals establish underwater exploration through physics principles. Atmospheric pressure at sea level of 14.7 psi doubles every 33 feet. Boyle's Law enables air space compression & expansion. Henry's Law reveals nitrogen absorption creating decompression requirements. Regulator systems reduce 3,000 psi to 140 psi enabling breathing. Buoyancy control devices enable neutral buoyancy achievement. Neutral buoyancy mastery enables motionless positioning. Emergency procedures enable out-of-air survival. Open water certification requires 12-15 classroom hours, 5-6 confined water sessions, 4 minimum open water dives.