Show the body, and then show the food going down the body, but it really depeneds on whst type of project you are doing.
An experiment can prove or disprove a hypothesis.
Prove causation
Experiment
That depends on the result of the experiment. The experiment is a way to test a hypothesis, and it's completely fine if the experiment disproves the hypothesis. Ideally, though, the experiment will support the hypothesis.
Galileo
to prove it worked.
An experiment can prove they are wrong or right ...:)
This was an experiment to prove universal gravitation!
An experiment can show: Cause and effect (Apex).
By experiment.
The first step is to decide on the purpose of the experiment. What is it that you are trying to prove or disprove.
look before you leap