Pumpkin Oobleck Made with Real Pumpkin

Playing with cornstarch and water (oobleck) is a wonderful sensory experience enjoyed by kids of all ages. It is also a great science exploration of a non-newtonian fluid. Turn standard oobleck into a Halloween activity by making pumpkin oobleck with the insides of your carved pumpkin.

Halloween Science: Pumpkin Oobleck

Pumpkin Carving Leftovers

jack o'lantern

We carved a pumpkin (and by we, I really mean my husband). Aiden chose the pattern he wanted, and Patrick set off to work. I was instructed to save the pumpkin seeds for roasting later. This meant I had the lovely task of separating the seeds from the rest of the pumpkin goo scraped from the inside of the soon-to-be jack o’lantern. If I were going to go to all of that trouble, I surely could find a use for the leftover pumpkin goo. And thus, pumpkin oobleck was born.

Pumpkin Oobleck


  • insides of a pumpkin minus the seeds
  • water
  • blender
  • cornstarch


  1. Separate the seeds from the inside of the pumpkin. (Save those for roasting.)
  2. Place the pumpkin goo in the blender with some water. Blend.
  3. Keep adding water and blending until you get a smooth, thin consistency.
    pumpkin oobleck
  4. Add 1/2 cup of cornstarch to an empty bowl.
  5. Take 1/2 cup of your pumpkin goo and slowly add it to the cornstarch until you have the consistency you like.

Usually a 1:1 ratio of cornstarch to water (or in this case pumpkin goo) works well. Just play with amounts until you are happy. You can also give your child free reign over mixing the two ingredients together. (Most children will eventually add all that you give them together, so you might want the amounts to be similar. If you have too much water or pumpkin goo, you’ll end up dissolving all of your cornstarch.)

pumpkin oobleck

The Feel:

The pumpkin oobleck does not feel like a regular cornstarch and water mixture. It is not as smooth. It still feels really cool and behaves like oobleck. My son had fun playing with it and throwing it all over the back patio. (It’s messy, so we took it outside.)

More Oobleck Fun

What are your favorite ways to play with cornstarch and water?

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This post was originally published on October 23, 2012.

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