Summary
Introduction
What happens when you add iron filings to regular slime? You get magnetic slime! Make your own magnetic blob that will swallow up a magnet in this fun experiment.
Materials
- Washable school glue (1/2 C)
- Water (1/2 C)
- Baking soda (1/2 tsp)
- Contact lens solution that contains both boric acid and sodium borate (2 tbsp)
- Iron filings (at least 1 tbsp)
- Measuring spoons
- Measuring cup
- Mixing bowl
- Spatula
- Paper towels
- Neodymium magnet (Exact size does not matter. The magnet shown in this project is a 1/2 inch diameter cylindrical magnet.)
- Optional: Food coloring
- Optional: Disposable gloves
Prep Work
Instructions
Neodymium magnets are very strong. Adult supervision is recommended when using them. Do not let the magnets slam together. They may pinch your fingers or crack. Keep them away from small children, pets, credit cards, and pacemakers.
- In the mixing bowl, thoroughly mix 1/2 C water and 1/2 C glue. Optionally, add a drop of food coloring.
- Add 1/2 tsp baking soda and mix completely.
- Add 2 tbsp contact lens solution and stir vigorously until the mixture starts pulling away from the edges of the bowl.
- Use your hands to knead the slime for several minutes. Do not worry if the slime is sticky at first; it will thicken as you knead it. If you do not want to get your hands messy, wear disposable gloves.
- Sprinkle about 1 tbsp of iron filings onto your slime. Knead the iron filings into the slime until they are evenly distributed and your slime has a uniform color.
- Slowly bring a neodymium magnet near the slime.
What happens as you bring the magnet near the slime?
- Pull your magnet out of the slime. Tip: You may find it difficult to remove bits of slime and iron filings from the magnet. Use a damp paper towel to help wipe them off.
- Keep trying to use your magnet to manipulate the slime.
How close can you get the magnet to the slime without the slime grabbing the magnet? Can you "steer" the slime in a certain direction with the magnet?
- Try dropping your magnet into the slime.
Watch the magnet for a few minutes. What happens?
Cleanup
What Happened?
When you add iron filings to your slime, the slime becomes magnetic! The slime is attracted to permanent magnets and will move toward them, even jumping up to "grab" them if you get too close.
Digging Deeper
Your neodymium magnet is a permanent magnet. It is always surrounded by an invisible magnetic field that pushes and pulls on any other magnets nearby.
The iron filings you added to your slime are ferromagnetic. They are not permanent magnets, but they can be temporarily magnetized by a nearby magnetic field, like the one from your neodymium magnet.
When you bring the neodymium magnet near the slime, the iron filings are attracted to the magnet. However, the slime is very viscous, so it moves slowly at first. The magnetic field gets much stronger very close to the neodymium magnet, so when you get too close, the slime will suddenly jump up and grab the magnet.
If you let go of the magnet, the slime will eventually "swallow" the magnet as the iron filings slowly wrap around it.
Ask an Expert
For Further Exploration
- Try using your phone to film a slow-motion video of the slime grabbing onto the magnet, or a time-lapse video of the slime slowly swallowing the magnet.
