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Zucchini Osmosis Experiment

Updated: Jun 7

Did you know a zucchini is made up of 95% water? See for yourself in this experiment!

This experiment uses a knife, ask an adult for help. 


  • Salt

  • Zucchini

  • Knife

  • Sheet pan

  • Paper towel

  • Kitchen scale

  • Notebook

  • Pencil

  • Camera (optional)



  1. Line the sheet pan with a paper towel.

  2. Cut two 1-inch-thick coin-shaped slices from a large zucchini and weigh each with a kitchen scale. Write how much they weigh in your notebook.

  3. Place the zucchini slices on the paper towel-lined sheet pan.

  4. Lightly coat one zucchini coin in salt. Leave the other salt-free as a control.

  5. Optional: set up a camera to record a time-lapse or video you can fast-forward of the zucchinis.

  6. For the next 30 minutes, check on the salted zucchini slice every 5 minutes. If the salt is wet, scape it off and replace with a new layer of dry salt. If your camera is shooting video and has stopped recording, hit record again.

  7. When the 30 minutes is up, stop recording. Scrape the salt off the one zucchini slice and weigh both the slices again. Did they gain or lose wait? Which one gained or lost more? Why do you think that is? Answer in your notebook.

  8. Watch the time-lapse/video or observe the paper towel to see how much water came out of the zucchini slice.


How does it work?

Salt is known as a hydroscopic substance. This means it attracts and absorbs any water around it. In the experiment, it attracted the water from the zucchini into the salt, and even overflowing it onto the paper towel.

A process called osmosis also helps draw out the water. You see, the water inside the zucchini contains less salt than the water on top of the zucchini. So, to fix this imbalance, the water inside the zucchini will start moving towards the high concentration of salt on top of the zucchini to try and dilute it. Eventually, the water to salt ratio will even out and there will be a balance.


Adapted from:



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