In which Miss Molly muses on pi and magnetism.

Happy PI DAY! YAY!pi

Who doesn’t love numbers? 3.14159265359 (etc) to be exact. Since it’s March (3) the 14th, 2015. So exciting. I have a fun storytime planned, but more of that next time. It’s all about math and patterning and pigs and cats. What? Those things don’t naturally go together? They do in Children’s Librarian Land. I’m actually excited about trying out a sneaky math storytime. As someone who had a math issue early on in her academic years, I have complete sympathy  for kids who might not fully LOVE and appreciate math. Especially when letters are thrown into the equation…that’s a very intentional math pun. Have I mentioned that I love puns?

Anyway, back to March’s Mangled Messes!

It was awesome. We delved into ferrofluids and made magnetic putty.

I purchased iron oxide powder to make it all work, and it couldn’t have worked better. Seriously, so great. I got 1 pound of it and have plenty left over. It has to be Black Iron Oxide (Fe3O4) otherwise it doesn’t behave correctly, despite the red being prettier. I know. I was tempted, too

We started off by talking about Ferrofluids which are liquids that become strongly magnetized in the presence of a magnetic field to amazing, and sometimes hypnotic effect. ferro2As I explained to the kids, anything considered ferrous means that it contains iron. Ferrofluid was invented in 1963 by NASA’s Steve Papell as a way to control liquid in the space, where there is no gravity. Simply apply a magnetic filed, and BAM, liquid control. You can potentially see why having liquid control in space might be important…say in the case of controlling fuel in a space ship.

Ferrofluid is made up of really tiny particles that are suspending in a carrier liquid, like oil. I made a bootleg version of this by combining some of the iron oxide powder with some cooking oil. It doesn’t behave quite as impressively as the the real deal, but it’s still darn awesome. When we moved the magnet toward the fluid, the iron oxide reacted in all sorts of crazy ways, making beautiful patterns, like the one above, though on a much smaller (and less elaborate scale) scale, like the image below. ferro

We played with that a  while and then dove into creating our own magnetic slime to take home. I used a recipe from Steve Spangler Science. We’ve made slime with recipe before (so I know it works.) I changed up the proportions a bit, to make it a little easier to handle.

Ingredients2015-02-25 18.41.11

  • /4 cup white school glue
  • Borax
  • Plastic cups
  • Measuring cup and utensils
  • Iron filings
  • Neodymium magnets
  • Water


  1. Empty the school glue into one of the plastic cups, red solo cups work well.
  2. Add about 1 tsp of iron filings to the glue. Stir well, but carefully.
  3. Measure 1/4-cup of water and pour it into another plastic cup.
  4. Add 1/2 teaspoon of borax to the cup of water and stir the solution.
  5. Add the borax solution to the mixture in the bowl.2015-02-25 18.42.29
  6. Mix it up VERY well, but slowly at first, so as not to slosh it around. The two solutions will congeal and become the slime. Not all of the liquid will be absorbed and this is ok.2015-02-25 18.43.33
  7. Remove the slime from the bowl or cup and place on a plate. 2015-02-25 18.46.46
  8. Hover the neodymium magnet near the slime and witness some ooey, gooey, slime-based magnetism. 2015-02-25 18.48.55Just be careful not to let the magnet touch the slime. The magnetic filings will get sucked right out and it becomes a mess.

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