Shrink or Grow? Gummy Worm Experiment

Did you know that gummy worms were invented in 1981, almost 60 years after the first gummy bear? Hans Riegel, a factory worker in Bonn, Germany (who later went on to start the Haribo company) originally made the bears with black licorice, which isn’t my jam. But that paved the way for worms, inspiring one of my favorite childhood treats: dirt and worms. Maybe that’s why this experiment grabbed my attention when I was browsing “The Curious Kid’s Science Book.” When submerged in different substances overnight, will gummy worms shrink, grow or stay the same? It’s a pretty simple setup (minimal supplies most of you already have at home) with a fun ending. Plus, there will surely be leftover worms for you to gobble up!

Gummy worm image
Original image by Willis Lam; background added

Materials Needed:

  • Smooth gummy worms
  • Cups or Ziploc bags
  • Salt
  • Sugar
  • Vinegar
  • Soda
  • Juice
  • Water
  • Optional: Printable data table

Note: Feel free to choose different ingredients to submerge the gummy worms. Be mindful of ingredients that would be harmful for children to ingest.

Acids and bases chartfrom “Acids and Bases” by Daniel Faust


  1. Select ingredients you’d like to experiment with.
  2. Using this data table – or creating your own – make predictions about what you think will happen to the size of the gummy worms when submerged in different ingredients.
  3. Label your cups (or Ziploc bags).
  4. One at a time, submerge gummy worms in different dry or liquid ingredients.
  5. Allow enough time for a change to take place. I’d recommend letting them sit and soak overnight for a fun surprise the next morning.
  6. Check to see if your predictions were correct! If you’d like, fill out the last column on the data table to compare. Were there any surprises?

Bonus: If you dare, try microwaving a gummy worm on a plate to watch it expand. 

Gummy worm experiment