Cornstarch Slime

CORNSTARCH SLIME This is a “hands-in” slime that seems to be both liquid and solid. The cornstarch and water mix creates a substance that can be hard when you squeeze it in your hands and an ooz- ing liquid mud when you release it. Adding color makes it even more interesting.

It was a big relief when it fell off! I was doing this activity with a particularly energetic group of six- and seven-year-olds. They loved the “slime that is both a liquid and a solid”; the cool colors, the textures and the ooze thrilled them all. In their enthusiasm, the children had spread the mix over a large part of their bodies and clothing. As the activity wound down, my biggest concern was keep- ing the mess out of the indoor classroom; secondarily, I thought about their parents’ car upholstery. Before going inside, we went to the play yard and began a game. The cornstarch began to dry and completely fell off the children and their clothing! I follow each cornstarch slime session with outdoor play and have not been afraid of cornstarch mess since.

MATERIALS: Cornstarch * Food coloring * Mixing bin * Water

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How to: 1. Put the cornstarch in the bowl or bin.

2. Add several drops of coloring.

3. Stir water a little at a time until your mix is no longer powdery. It is a delicate balance between too much water and too little. Start with one cup of water for 16 ounces of cornstarch and then go from there.

4. Play with the mixture; see that it is solid when you squeeze it and an oozing liquid when you let it flow.

How to present it to your group: 1. Set up several bowls or bins with cornstarch; have one bin for every 4-6 students.

2. Use approximately 16 ounces of cornstarch for every 6 students.

3. Set up buckets or bins of water for students to rinse off the cornstarch. This keeps everybody from using the sink and dripping on the floor.

4. Color each bin differently so students can move from bin to bin.

5. Explain how exciting it is to have slime that is both a liquid and a solid. Talk about the reasons for the suspen- sion mix. Remind them that cornstarch is in a lot of the food they eat.

6. As students rinse their hands in the bucket and then go back to the cornstarch bins, the mix gets watery. Have some extra cornstarch available to replenish the slime.

The lesson: The cornstarch molecules (solids) are suspended in the water (liquid) much like quicksand. The cornstarch molecules slide by each other when you drip them like a liquid. When you tighten your hand on them, they clump together and feel solid. Preschool science version: Mixing, demonstration and explanation take about 5 minutes. Playing with the slime takes anywhere from 15 to 30 minutes. Cornstarch and water slime is an engaging textural and tactile experience for preschool students. Divide your class into groups of four and give each group their own bin of slime so that everyone feels it and comments together. This can be done indoors and outdoors but is easier to clean up outside.

Vocabulary: Suspension, molecules, liquid, solid