Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

How Does Slime Work?

Kate Biberdorf is known as Kate the Chemist and she does science experiments for kids.
Dustin Meyer
Kate Biberdorf is known as Kate the Chemist and she does science experiments for kids.

What is slime and how do you make it? What makes glue sticky? Why does mixing diet coke and Mentos make an explosion? How does glow in the dark stuff glow without batteries?

Download our listening guide: PDF | Google Slide| Transcript | Puffy Slime Recipe
We're talking about sticky things like slime and glue in this episode. Plus, bonus: explosions! The branch of science we're focusing on is called chemistry. Chemistry is basically the study of stuff and what it's made of, and how different substances interact with one another, sometimes even combining to make new stuff. Our guest is Kate Biberdorf, professor of instruction at the University of Texas, better known as "Kate the Chemist." Her new book is called The Big Book of Experiments.


"I made slime out of glue, baking soda, water and detergent. I want to know why that worked?" - Sophia, Hinsdale, Illinois

Slime has a recipe, just look cookies or cake or anything else you'd bake.

"In slime, everything has a role, but the main two pieces you have to have are glue, because glue contains polyvinyl acetate, and then you have to have something that provides a source of boron," said Kate. She recommends contact lens solution because it definitely has boron in it. The detergent Sophia used probably had boron in it as well.

"When the boron and the polyvinyl acetate come together, that's how you form a beautiful polymer." A polymer is a big long molecule.

Slime is sticky because the molecules in the polyvinyl acetate want to stick together, but they've formed bonds with the boron in a longer chain called a polymer.

"Everything else is kind of for fluff. Water gives it a nice texture. I like to add shaving cream to mind to give it a nice puffiness," Kate said.

Bubble Snake

Credit Dustin Meyer
Bubble snake

Kate also shared her bubble snake experiment with us. You're going to want to do this outside.

  1. Cut a plastic soda bottle in half. Use a rubber band to strap an old rag to the bottom of the soda bottle.
  2. In a small bowl mix half a cup of water with quarter cup of dish soap, stir it up.
  3. Flip the soda bottle over so you're looking at the rag, color the bottom with food coloring.
  4. Turn the bottle back over and dip it into the bubble water. Let it drain.
  5. Bring it to your mouth and blow through the bottle end. You'll get a giant bubble snake!

Melody is the Contributing Editor for But Why: A Podcast For Curious Kids and the co-author of two But Why books with Jane Lindholm.
Jane Lindholm is the host, executive producer and creator of But Why: A Podcast For Curious Kids. In addition to her work on our international kids show, she produces special projects for Vermont Public. Until March 2021, she was host and editor of the award-winning Vermont Public program Vermont Edition.
Latest Stories

But Why is a project of Vermont Public.

vermont public logo