An experiment to learn more about water displacement or Archimedes' Principle.
Materials: Download the PDF version of this project for printer-friendly English and Spanish version, plus teacher notes.
PROBLEM: When you squeeze the sides of the bottle, why does the diver
RESEARCH: Read about a man named Archimedes, who lived in ancient Greece.
Find out what he discovered when he was in the bath. What does displacement
HYPOTHESIS: What do you think happens to the weight of the diver when you
squeeze the sides of the bottle?
2 liter bottle with cap
- Fill the bottle full of water.
- Fill the eyedropper about 2/3 full of water.
- Put the dropper into the bottle and screw on the cap. Be sure the diver
floats before putting on the cap.
- Squeeze the sides of the bottle. Release the sides and observe what
- Record your observations in your data table.
DATA: Make a data table to record your observations and inferences.
CONCLUSION: This is not optional. You must explain what you learned by doing
this activity. Remember that you must answer the question you asked in your
original problem statement.
NOTE: BE SURE TO HAVE YOUR PARENT OR GUARDIAN SIGNS YOUR WORK.
PARENTS: YOUR SIGNATURE SHOWS YOUR STUDENT HAS DONE THE WORK.
Here is a secret to help you see what you are supposed to see. Watch what happens to the air bubble in the dropper. Try to explain what you see.
POSSIBLE HYPOTHESIS: The diver will fall when the sides of the bottle are squeezed because the squeezing pushes it down.
POSSIBLE CONCLUSION: The diver falls because the air is compressed into a smaller space and becomes denser, weighs more. The bubble in the dropper got smaller. The diver comes back up because the air expands and is less dense.