Tuesday, November 25, 2014

Recipes for Slime

Science teachers, make some slime and let the kids play!

I was a middle school science teacher for many years, and now I am privileged to teach future teachers how to teach science. Every science teacher should know how to make slime. The kids love it, and there can be fantastic science learning that happens by playing with slime!

My two favorite slimes are easy to make, and don't require any chemicals other than those you can probably find at your local grocery store. Here are the recipes for oobleck and glurch...

(Read Bartholomew and the Oobleck by Dr. Seuss before making this slime!)
  • 2 parts cornstarch 
  • 1 part water 
  • a few drops of green food coloring 
A batch of Oobleck I mixed up for class.
Look at that lovely ooze...
Stir together in a large container. Mix well! If too runny, add a little more cornstarch. If too stiff, add a little more water. You’ll know when it’s oobleck.

I drop this stuff by handfuls onto students' work area. It's a weird slime in that the more pressure you put on it, the more solid it becomes (you can roll it into a ball like playdough), but as soon as you stop putting pressure on it, it will "melt" back into a puddle of goo. Lovely!

If kids get this stuff on their clothes, it washes right out (it's just cornstarch!) It's easy to clean up too; just a wet paper towel followed by a dry paper towel.

Note: DON’T keep this stuff for more than a day! It will grow fungus in 24 hours and it will to stink to high heaven. To get rid of it, scoop it out into the trash.

Glurch (Half glue, half starch, all slime…) 

  • 2 parts white glue (I like Elmer’s) 
  • 3 parts liquid laundry starch (I like Sta-flo) 
  • a few drops of food coloring, if you like 
Pour glue and laundry starch into a sandwich-size zip-top baggie and add food coloring. Knead together for about 5 minutes. Let it rest for about 20 minutes or so. Knead again like crazy until it comes out about like silly putty. If there is any extra liquid left, pour it out. If too sticky, add a few more drops of laundry starch.

Keeps quite well if you keep it in a baggie and squeeze out as much air as possible.

If you can't find liquid laundry starch, you can try this recipe too, though it isn't quite as simple and straightforward:

  • Solution A:
    • Equal parts white glue and water (half a cup of each?)
    • A few drops of food coloring, if you like.
  • Solution B:
    • An equal amount of water to the total volume of Solution A (If you followed the suggestion above, a cup of water will do.)
    • Stir in Borax (find it in the aisle by the laundry detergent) until you can’t dissolve any more. (We call this a saturated solution.) :-)
  • Mix the two solutions together and they will form a gloppy mass. Remove the mass from the solution, and knead it like crazy for a few minutes. If there is any liquid left, pour it out.

If you decide to have a slime day in your class, share your story! What did you do? What did the kids learn? What did you learn in the process?

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