(photo courtesy of Microsoft Clipart)
Recently Lindsay sent me an article that sounds like it could be lots of fun with chidren. It is actually a lesson in the changing of matter--which I know sounds a bit technical. After reading it I thought with the right preparation and presentation preschoolers would probably love this. It involves making jello, and a corn starch mixture, and ice--always fun to play with these kinds of things.
Ice Cubes, Jell-O and Corn Starch
By Lindsey Wright
These days my teaching is usually confined to music, but every now and again I have the pleasure of being in charge of a kindergarten or preschool class. This is an activity I learned when I was in school myself, and have since used to entertain and delight several classes. To try it in your class, you'll need the following:
● 1 box (16 oz.) of cornstarch
● 1 box of Jell-O gelatin mix
● 2 mixing bowls
● 1 cookie sheet
● 1 glass pitcher
● 2 ice cube trays
● food coloring (optional)
The point of the activity is to teach the students about how matter can easily be changed, especially at different temperatures. Starting with just water, corn starch, and Jell-O mix, you end with solid ice cubes, semi-solid Jell-O, and a non-newtonian fluid (a mixture that is solid when pressure is applied, but liquifies under normal conditions). When I host this activity, I have a student pour the water from the pitcher into the ice tray. While the water is freezing, I mix up a batch of Jell-O, show the students that it's a liquid and leave it to set in the fridge, explaining what will happen. Once both are done, I show the students how the water has expanded and that it then floats in the same pitcher it came from. I also show them that the Jell-O has turned jiggly and explain that it's neither liquid nor solid; then serve ice water and Jell-O.
However, the most fun part for the students happens while the ice and Jell-O are in the fridge. Mixing the corn starch with 1 ½ cups of water creates the non-newtonian solution, and the children will have loads of fun experimenting with it. Ideally, each student should either have their own batch of solution to fiddle around with or get a turn manipulating the material. Adding food coloring (perhaps even different colors to multiple batches) can make the activity even more interesting.
The trick with this activity is timing. You can either set the finished products up ahead of time, or space the activity out through the course of a day. Both have their advantages, but if your students are more prone to distraction, it might be best to have the results ready for swifter gratification.
You should first determine how you would like to carry it out: whether to include the students in the creation process, or get everything ready ahead of time. If you're going to do things yourself, you shouldn't have much trouble, all the mixing is very straightforward and you only need a couple minutes for each. You will want to start the Jell-O and ice well ahead of time if you want to reveal the results of the experiment immediately (accomplishing the lesson this way should work somewhat like a cooking show: mix the substance in front of the students, then produce the finished product while explaining how it changed). However, you won't need to do this if you want to reveal the finished products later in the day, but since the student's aren't as involved they may lose some of their enthusiasm in the meantime.
If you think your students are disciplined enough, then have them help conduct the experiment. In this case, you may want to stretch the activity across enough time for the Jell-O and ice to form so the children can see the difference for themselves. They'll feel more accomplished knowing that they've made something than they would if their contribution were redundant to the final product. Have them fill ice trays and mix the Jell-O first, then the cornstarch solution. This way the substances that take time to reach their solid and semi-solid state will do so while the students are occupied. You can even be a bit sneaky using the cooking show technique to produce the end results early (when the kids are done playing with the cornstarch paste) so that the activity can come to fruition in a more timely manner.
(A word of caution: It is important that you throw the corn starch solution away in the trash. If you attempt to dispose of it in the sink, it will clog beyond the ability of any plunger.)
This activity is a fun way for young students to learn about states of matter and to see the weirdness that basic chemistry can create. Like most potentially messy projects, it can be a lot of fun or it can be a complete disaster. Be sure to never let the corn starch leave your sight and be ready with paper towels for any sudden spills. If all goes well, your students will learn something, have a lot of fun and end up with a tasty snack.
Lindsey Wright is a music tutor, computer repair consultant, and substitute teacher in Washington State.