Have you ever thought about whether an orange would float or sink in water? Doesn’t seem like something that really matters, but testing it will help you learn something about density as well as learning something about oranges you didn’t know before.

For this experiment, you will need:

  • One orange
  • A container such as a deep bowl
  • Water

What to do:

Fill the container with water to about an inch from the top. It needs to be deep enough that the orange will clearly be seen to sink or float.

Put the orange in the water and make a note of what happens to the orange.

Remove the rind from the orange and again, put it in the water. Make a note of what the orange does.




What happened when you put the orange in the water the first time? It floated, right? Then after you removed the rind and put it in the water, that same orange sank, didn’t it? Why would this happen?

The orange’s rind has a lot of very small pockets of air in it. These pockets are the reason the orange floated the first time. The pockets of air gave the orange rind a low density and thing with low density, like the foam pool noodles are made of, will float. When you removed the rind, the orange lost its low density coat so then it sank when put in water.

What is density? It is simply how solid an object is. Two things can be the same size but have different densities. One may be heavier because it is more dense. The other may be lighter because it has tiny air pockets that take up space and makes it less dense. It is easy to find many items that are the same size but have different weights. You can test them in water, if they won’t be ruined by water, in the same way you tested the orange.