Crawling Magnetic Slime

July 29, 2025

On Tuesday, July 29nd, we returned to the Wardlaw-Hartridge School to explore magnetic slime!

This time, we brought back a live demonstration with a twist, slime that moves with a magnet! It was our fifth time hosting a session at Wardlaw-Hartridge, and while kids asked fewer questions during the science portion, they formed a huge line afterward just to play around with the slime and magnets! It was a big hit.

Here’s what the students learned:

Magnetism and Iron Filings: Students discovered that by mixing iron filings into slime, the slime becomes responsive to magnets. When a strong magnet is held near it, the slime stretches and creeps toward the magnet as if it’s alive! This is because the iron inside the slime is attracted to the magnetic field.

Polymers and Viscosity: We also touched on how slime is a polymer, a stretchy material made by linking many small molecules together. The thick, gooey texture is what makes the slime move slowly and smoothly when the magnetic forces pull on it. Students could see how the slime oozed and crawled when the magnet was moved around!

Before we explained the science behind it, we had students guess what might make the slime move. Some thought it was magic, while others guessed something metal was inside the slime, and they were right! The hands-on time was the highlight. Students loved using the magnets to “chase” the slime around the table, and we heard lots of excited laughter and curious experimenting.

Stay tuned for more experiments, and if you want to be a part of ChemZoo, sign up to be a chapter director or a volunteer in your state. ChemZoo is all about making science accessible and fun, because our generation needs more scientists.