Watertight doors are designed to resist as much ______ as the space they separate.

Watertight doors are designed to resist as much ______ as the space they separate.

• A. Temperature
• B. Friction
• C. Mass
• D. Pressure

Answer: (D)

Watertight doors are designed to withstand the pressure difference between the spaces they separate. Water exerts hydrostatic pressure that grows with depth, so the door and its seals must resist that force to prevent water from seeping through. The greater the water level on one side, the higher the pressure pushing on the door, and the stronger the door’s hardware and gasket need to be to keep it closed and watertight. Temperature, friction, and mass aren’t the factors that determine a watertight door’s effectiveness in keeping water out; those elements aren’t what stops water from moving through the gap. Temperature isn’t about resisting water ingress, friction isn’t the sealing mechanism, and mass doesn’t relate to the door’s ability to hold back pressure. Pressure is the key concept here.

Watertight doors are designed to withstand the pressure difference between the spaces they separate. Water exerts hydrostatic pressure that grows with depth, so the door and its seals must resist that force to prevent water from seeping through. The greater the water level on one side, the higher the pressure pushing on the door, and the stronger the door’s hardware and gasket need to be to keep it closed and watertight.

Temperature, friction, and mass aren’t the factors that determine a watertight door’s effectiveness in keeping water out; those elements aren’t what stops water from moving through the gap. Temperature isn’t about resisting water ingress, friction isn’t the sealing mechanism, and mass doesn’t relate to the door’s ability to hold back pressure. Pressure is the key concept here.