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20 Minute Labs: Pumpkin Guts Slime

20 minute labs logo | Yellow Scope


pumpkin guts | Yellow ScopeHappy October! It's autumn, and for many of us, that's a time for making Jack-o-Lanterns! One of the first steps is to cut off the top of a pumpkin and scoop out the insides. The rest involves the shell of the pumpkin - but what about those guts?

Maybe you've roasted the seeds for a yummy snack? Or maybe you compost the pumpkin innards. But have you ever made pumpkin slime?!

owl jack-o-lantern | Yellow Scope

If you've followed us at Yellow Scope for awhile, you know we love slime! From our 6 Recipes of Slime to Rainbow Slime, we're big fans. But now that it's October, we wondered if we could make some special Hallowe'en slime!

In this month's 20 Minute Lab, we'll use pumpkin pulp and some common household ingredients to make ooey, gooey slime!

Safety Warning: If you have a pumpkin allergy, touching pumpkin pulp and seeds can irritate the skin or cause hives. Try a recipe from our other slime blogs (see links above)!

  • pumpkin slime ingredients | Yellow Scope
    1 medium bowl
  • 2.5 oz clear Elmer's glue (half a typical 5 oz bottle)
  • 1/2 teaspoon water
  • 1/2 teaspoon baking soda
  • 1/4 cup pumpkin pulp with seeds (a small pumpkin will do!)
  • 1 tablespoon contact lens solution (containing boric acid)
  • 1 spoon
  • 1/4 cup measuring scoop
  • measuring spoons
  • Optional: plate and two forks (for separating out excess seeds)


  1. pumpkin guts scoop and separate | Yellow Scope
    Cut your pumpkin in half and scoop out 1/4 of the pulp and seeds with the measuring cup.
  2. Optional: some pumpkins have a lot of seeds and little 'goop'. If you want, you can put the contents of your pumpkin onto a plate and use two forks to separate out the excess seeds, so you have more goop to add to your slime.
  3. add solution to pumpkin slime | Yellow Scope
    Add the glue and water to the bowl and mix together with the spoon.
  4. Add the baking soda and mix.
  5. Add the pumpkin guts and mix.
  6. Add the contact lens solution and mix again, this time using your hands! Continue to mix until the slime comes easily away from the walls of the bowl.
  7. Now you have your slime! Squeeze and stretch to your heart's content!


pumpkin guts slime  | Yellow Scope

What makes slime so satisfying? Well, it looks pretty cool, but the essence of slime is its texture. It's liquidy enough that it will squeeze through your fingers, but solid enough it won't just pour out of your hands. Something that has both liquid and solid qualities at the same time is called a non-Newtonian fluid.

Let's start with the glue. Glue is made of long molecules called polymers. Polymers are long chains of repeating units, like small sections of necklaces. Glue is made up of lots and lots of these little units of polymers that can slide over each other; this is what makes glue flow like a thick liquid.

Contact lens solution contains boric acid. The borate ions linked up with the glue, thickening the polymer - kind of like if you started tying the necklace sections together. They still flow, but not as well. This made the glue solution stiffer.

polymers | Yellow Scope

This cross-linking of glue molecules is what creates slime. If you put your pumpkin slime in a small bowl or muffin tin, it slowly acts like a liquid and will mold to the shape of the container. But when you apply pressure, it hardens up and feels more like a solid. What fun!


Let us know how your experiments turned out! Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

For more exciting experiments, check out our Yellow Scope science kits on the Shop tab of our website!

Chelsea Schuyler
Chelsea Schuyler