This has to be one of the coolest slime you will ever make. If you want to learn how to make magnetic slime with iron oxide powder, this is about as simple as it get. All you need is liquid starch and the secret, magnetic ingredient for a very exciting science demonstration. Slime is an excellent science and sensory play activity for kids.
Magnetic Slime Recipe
SUPPLIES:
- 1/2 cup black iron oxide powder
- 1/2 cup PVA White School Glue
- 1/2 cup liquid starch
- 1/2 cup water
- Measuring Cups, Bowl, Spoon or Craft Sticks
- Neodymium Magnets (our favorite is the cube shape)
HOW TO MAKE MAGNETIC SLIME
NOTE: Adult assistance required! This slime can be easily made ahead of time and used for many days afterward. The mixing process can get a little messy and should not be done by younger kids.
STEP 1: Pour 1/2 cup of glue into a bowl.
STEP 2: Add 1/2 cup of water to the glue and stir to combine.
STEP 3: Add a 1/2 cup of the iron oxide powder and stir to combine. This is probably best left for adults to do as the powder can get everywhere quickly.
We did not find that any of the particles flew around but I would not recommend spending to much time inhaling the open bag.
You will notice that this mixture is more grey to start out with, but the end result will be a very black and glossy color.
STEP 4: Measure out a 1/2 cup of liquid starch and add to the glue/water/iron oxide powder mixture.
STEP 5: Stir! Your slime will start to come together immediately but keep stirring.
It will begin to darken so don’t worry if it still appears gray. There will be liquid leftover from this slime in your bowl. Transfer your slime to a clean, dry container. I would suggest letting it set up for 5-10 mins.
Time to have fun and test out your magnetic slime! Grab your magnets and see what happens.
WHY DO YOU MAKE A MAGNETIC SLIME?
Because it’s incredible! There are two essential ingredients needed to make and enjoy this super-strong magnetic slime recipe, iron oxide powder and a neodymium magnet.
You can also use iron filings, but we chose the powder after a simple search on Amazon for what we wanted. The powder we purchased, although pricey, came well packaged and will make many batches of slime for us.
A neodymium magnet is also known as a rare earth magnet, which is actually pretty different than the regular magnets you are probably accustomed, too.
A rare-earth magnet has a much stronger force field and is made of different materials which is why it works with the iron oxide powder or fillings over a traditional magnet. You can read a little more about these magnets here.
We tested our regular magnetic wand on this iron oxide powder slime, and nothing happened! You always have to check and see for yourself. We purchased a bar shape and cube shape neodymium magnet, but the cube shape was the most fun.
MORE FUN WITH MAGNETS
Below, you can see our cube-shaped neodymium magnet engulfed by the magnetic slime. It’s very cool how the slime will completely crawl around the magnet and bury it inside.
THE SCIENCE BEHIND OUR SLIME RECIPE
We always like to include a bit of homemade slime science around here! Slime is an excellent chemistry demonstration, and kids love it, too. Mixtures, substances, polymers, cross-linking, states of matter, elasticity, and viscosity are just a few science concepts that can be explored with homemade slime!
What’s slime science all about? The borate ions in the slime activators (sodium borate, borax powder, or boric acid) mix with the PVA (polyvinyl acetate) glue and form this cool stretchy substance. This is called cross-linking!
The glue is a polymer made up of long, repeating, and identical strands or molecules. These molecules flow past one another, keeping the glue liquid. Until…
You add the borate ions to the mixture, and it then starts to connect these long strands. They begin to tangle and mix until the substance is less like the liquid you started with and thicker and rubbery like slime! Slime is a polymer.
Picture the difference between wet spaghetti and leftover spaghetti the next day. As the slime forms, the tangled molecule strands are much like a clump of spaghetti!
Is slime a liquid or solid?
We call it a Non-Newtonian fluid because it’s a little bit of both! Experiment with making the slime more or less viscous with varying amounts of foam beads. Can you change the density?
What can you do with magnetic slime? We love watching the magnet get swallowed up by the slime. It never gets old.
If you happen to get some magnetic slime on clothing? No worries! Check out our tips for how to get slime off clothes and hair.
MORE MUST TRY SLIME RECIPES
Printable Slime Science Guide
Once kids understand why slime stretches, snaps, and flows, the next step is testing it themselves.
This printable Slime Science Guide turns slime into a simple investigation instead of just a one-time activity. Kids compare textures, record results, and experiment with different ingredients while practicing observation skills.
The activities connect to real science concepts like polymers, viscosity, and material properties but stay easy to run at home or in a classroom.
Included:
- investigation pages
- observation charts
- variable testing ideas
- simple explanations kids can understand
Thank you so much for publishing this recipe! At my son’s request, we ordered red iron oxide powder (he thought it would look better than black). We just made our first batch of magnetic slime and it is not at all magnetic:(. I have 4 stacked neodymium magnets and nothing happens. It there something different about the black iron oxide powder? Have you tried red?
Thank you!
I got my answer! Red and black have different t chemical formulas and therefore, different magnetic properties. Must use black like your recipe states.
Any ideas for what to do with 5lbs of red iron oxide???
I just have a question. I really want to do this with my students but I have a concern about the black color. Does it stain? I did a project with black food color and it was a mess. Just trying to avoid a repeat. This recipe sounds too good not to try.
I appreciate your time and fun activities.
can we use normal magnet
Love these recipes are super useful for a stall I am running where we are selling slim and putty ! Thank you for these great recipes!
– RainbowGal1245
No you can not. You need the special one!
We did not have an issue with it staining once it was incorporated. You need to mix gently.
I would like to know how to store the slime. My friend and I just made a batch of it but I haven’t seen anywhere how to store it.
Store in a reusable container.
Hello, i don’t live in the US so iron oxide is not wasy to come by. I can only find iron oxide used to color cosmetics. Will this work as well?
I do not believe it will have the same effect unfortunately. However, it’s worth a try for an experiment. Can you not order from Amazon?
This sounds incredibly cool! But how long does this slime keep if stored properly?
We have kept if for a couple weeks!