Vacuum or ______ pulls the water up through the suction hose and out the discharge hose.

Vacuum or ______ pulls the water up through the suction hose and out the discharge hose.

• A. VENTURI EFFECT
• B. PUMP ACTION
• C. GRAVITY FEED
• D. CAPILLARY FORCE

Answer: (A)

The suction is produced by a Venturi effect, which is a practical use of Bernoulli’s principle. When a fluid is forced to flow through a narrow throat, its velocity increases and its static pressure drops. That pressure drop in the constricted section creates a vacuum in the surrounding suction line, so atmospheric pressure at the water surface pushes water up into the suction hose and through the discharge hose. This is why the term Venturi effect is used to describe how suction is generated without a separate pump. Gravity feed would rely on height differences and won’t explain suction through a hose in most setups. Capillary force is only significant in very small tubes and isn’t responsible for moving water through a typical boat hose. Pump action implies a mechanical pump driving the flow, rather than a pressure drop created by high-velocity flow through a constriction.

The suction is produced by a Venturi effect, which is a practical use of Bernoulli’s principle. When a fluid is forced to flow through a narrow throat, its velocity increases and its static pressure drops. That pressure drop in the constricted section creates a vacuum in the surrounding suction line, so atmospheric pressure at the water surface pushes water up into the suction hose and through the discharge hose. This is why the term Venturi effect is used to describe how suction is generated without a separate pump.

Gravity feed would rely on height differences and won’t explain suction through a hose in most setups. Capillary force is only significant in very small tubes and isn’t responsible for moving water through a typical boat hose. Pump action implies a mechanical pump driving the flow, rather than a pressure drop created by high-velocity flow through a constriction.