Here’s a fun experiment that shows you how much stuff can pass through a membrane. Scientist call it the  semi-permeability of membranes.


Before we start, take out your science journal and answer this question: What do you think will happen when we stick a piece of celery into a glass of regular water. Anything special?


What if we add a teaspoon of salt to the water? Now do you think anything will happen?
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11 Responses to “Membranes”

  1. Tamara Pyatt says:

    Could you please correct the answer to exercise 4? thanks!

  2. They are on the second page of the worksheet that is linked just below the video.

  3. Tamara Pyatt says:

    where can i find the answers to the exercises?

  4. Melanie Williamson says:

    thanks.

  5. No, but they do experience osmosis due to the difference in water concentration. Osmosis balances the water concentration between the high and low sides. There are several osmosis experiments in this section – enjoy!

  6. Melanie Williamson says:

    do the cells dissolve in the salt water?-Gabe’s cousin Wally

  7. Tammy Junker says:

    what about watermellon

  8. Martin Melody says:

    Nice

  9. Not all experiments will have the same results but putting the celery in the salt water should result in it being much flimsier and less weight. This occurs because the salt water will draw fresh water out of the vegetable. Be sure to add enough salt and let the celery soak for at least 45 minutes.

    If your results don’t improve try carrots or potato slices. Good luck!

  10. Michelle Raine says:

    We did this experiment and had some varying results. Mostly saw an increase in weight with the salt water solution. Jenna, Jessica and Joshua want to know why the celery absorbed that salt water solution and not the plain water?