At what depth does atmospheric pressure increase significantly?

At a depth of 33 feet of seawater, the pressure from the water above contributes significantly to the overall pressure experienced by a diver. This is because water exerts pressure based on its weight, and for every 33 feet of seawater, the pressure increases by approximately 1 atmosphere (atm), which is equivalent to the pressure at sea level.

Therefore, at 33 feet, divers are subjected to a total pressure of about 2 atm (1 atm from the atmosphere and 1 atm from the water). This depth is critical for divers as it marks the point where the effects of pressure become more apparent and require consideration for diving practices, such as equalization techniques and understanding how pressure affects gas volumes according to Boyle's law.

As divers go deeper, the increase in pressure continues, but 33 feet is the most significant point regarding initial pressure changes in recreational scuba diving. This depth is also commonly used as a reference point for various diving tables and training.