Experiment: How to make a potato float in water

Here follow my instructions for the floating potato experiment. This is a quick experiment that doesn’t take a long time to do. Can you make a potato float in water? How is it done? And why does it float, or doesn’t float?

Remember to start the experiment with a hypothesis, what do you think will happen?

Instructions for parents: Read this first.

Material included:

  • One potato
  • A bag of salt
  • Water

Additional things you will need:

  • A bucket


  1. Measure half a liter of lukewarm water in a bowl.
  2. Then put an uncooked, and unpeeled potato in the bowl.
  3. Add a tablespoon of salt and mix the salt into the water with a spoon. Take the potato out if necessary. Put the potato down again when the salt has been thoroughly mixed with the water.
  4. Does the potato flow? If not, add more salt to blend properly with the water.
  5. How much salt do you need to add for the potato to flow?
  6. Let the potato remain in the water with the salt for a couple of days and see if the potato still floats.


If the potato floats or not have to do with its and the water’s density. The potato has a higher density than the water and therefore it sinks to the bottom. When the salt is mixed in the water, it gets more density than the potato, and the potato floats.


To see others do the experiment look at this video where they use sugar instead of salt:

Do you have any questions or comments about the experiment? Just leave a comment below!

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i thougt that the potato would float because i did this experiment in my old school, and then it did work. and my little brother did this too in his school. but i thougt that if i put in more salt the potato will flew more easier. and i also thought that you need a small potato because a big potato is more heavey and the water would not lift it, but no.

I thought the potato would move but not in just one tablespoon because we needed 3 tablespoons?? but in the end the potato floated and I can send pictures to you on gmail on the potato that floated! but it was a fun and a little exciting but a we hear!

My hypothesis was that the more salt you would add to the bucket the better the potato will float. This is because the salt will effect the density of the water.
The experiment proved that my hypothesis were right the more salt i added the better the better the potato floated !

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