The student wants to explain how a siphon keeps flowing without a pump. Which choice most effectively uses relevant information from the notes to accomplish this goal?

Question

While researching a topic, a student has taken the following notes:
- A siphon moves liquid from a higher container to a lower one through a tube.
- Once the tube is filled, liquid flows without a pump.
- Gravity pulls the liquid in the longer, descending arm.
- Air pressure on the upper liquid's surface pushes liquid up the shorter arm to replace it.

Accepted Answer

A. Once the tube is full, gravity pulls liquid down the longer arm while air pressure on the upper surface pushes more liquid up the shorter arm to replace it.. Gravity on one arm, air pressure on the other: the mechanism.

Answer

B. A siphon moves liquid through a tube. — What it does, not how.

Answer

C. Siphons do not need pumps. — Restates the puzzle without explaining it.

Answer

D. One container is higher than the other. — The setup, not the mechanism.

Expression of Ideas practice question

Answer: A. Once the tube is full, gravity pulls liquid down the longer arm while air pressure on the upper surface pushes more liquid up the shorter arm to replace it.

Why the other answers are wrong

More Expression of Ideas questions