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.
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"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
Kate also shared her bubble snake experiment with us. You're going to want to do this outside.
- Cut a plastic soda bottle in half. Use a rubber band to strap an old rag to the bottom of the soda bottle.
- In a small bowl mix half a cup of water with quarter cup of dish soap, stir it up.
- Flip the soda bottle over so you're looking at the rag, color the bottom with food coloring.
- Turn the bottle back over and dip it into the bubble water. Let it drain.
- Bring it to your mouth and blow through the bottle end. You'll get a giant bubble snake!
