Recipe for Green Slime

Green slime has been a big hit with students--elementary through high school.  We "cooked" it better as the days went on.

Here's a rambling recipe:

Warm up 1 cup water in the classroom microwave--not boiling, just above room temperature

Put 1/2 cup cornstarch into a medium bowl.  Use a large spoon to stir in most of the warm water, adding water slowly.  Reserve just a little bit of the water in case you need more.  Stir in a couple of drops of food coloring.  Our favorite choice was green.  It's okay if it looks "marbled."

As you stir the slime it will look liquid then feel more solid as you drag the spoon around, trying to mix it.  The consistency will not be "consistent"--you're done mixing when you see puddles next to solid parts.

Scrape the mixture onto a Tupperware pastry mat, or some other non-porous surface.  If your tabletop is solid that will be okay, just be warned that the food coloring may stain a nice surface.  It stains our hands for a little while but washes off in a day.

Let the students grab the solid pieces of the slime and hold it in their hands.  It will soon warm up from their skin temperature and start dripping through their fingers.  Cool.

We ended the activity by putting the slime into some ziplock bags.  When students hold the bag the slime will semi-liquify again and be fun to squeeze.