Floating Fish

If you've ever been swimming, you know what happens if you stop moving. You start sinking! You can always spread out your arms and legs, but that only lets you float on the surface. So how do fish float in the water without rising up to the surface, or sinking down to the bottom? Let's investigate!

  1. Ages: 5 - 11

  2. 30 minutes - 1 hour

  3. Super messy

  4. Grownup needed

Step-by-step tutorial

  • Step 1

    1. Draw a different fish face on each balloon.

  • Step 2

    2. Put a marble in each balloon.

  • Step 3

    3. Fill each balloon and tie a knot in the end. - Balloon 1: add 1/3 cup vegetable oil- Balloon 2: add 1/3 cup water- Balloon 3: blow it up until it's the same size as the others

  • Step 4

    4. Put each balloon in a deep bowl or bathtub full of water and observe what happens.

  • Step 5

    5. Record your results! Draw or write what happened with each of your balloons.

  • Done!

    Keep experimenting! Can you change the buoyancy of your fish balloons? - Try adding more marbles - Try it without marbles - Try putting oil and water in the same balloonWhat happens to the balloons? (Tip: Fish balloons make great bath toys!)

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