Argo Corn Starch

I teach the 9-year-olds in Primary (Sunday School), and this week’s lesson was based on chapter seven in the book of Matthew:

Matthew 7: 24-27

  1. Therefore whosoever heareth these sayings of mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock:

  2. And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock.

  3. And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand:

  4. And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it.

At the end of the lesson, I wanted to illustrate that you can’t always rely on your own judgement in determining whether something is solid or not. And what better way to make that point than with non-Newtonian fluids?

So, in addition to the lesson manual and my scriptures, I packed up a pan, a large spoon, a measuring cup, and a Ziploc bag full of cornstarch, and headed to church.

The Primary lesson went quite well, and when it came time for our little object lesson, I sent two of the boys to the bathroom to fill the measuring cup with water. While they were gone, I showed everyone else the Ziploc bag with cornstarch. I explained that cornstarch was a very fine powder, similar to powdered sugar. (Food Science Fact: Most powdered sugar contains a small amount of cornstarch where it acts as an anti-clumping/anti-caking agent.)

A few of the kids asked if they could feel the cornstarch, but I knew that if I let them stick their fingers in the bag we’d end up with cornstarch everywhere, so I told them they could come up and feel the bag if they wanted to.

A few of the kids came up to the front and felt the cornstarch in the bag, but one of the little girls didn’t just feel the bag, she squeezed it. Hard. And…


The Ziploc bag, the opening of which was aimed straight at my face, exploded. It was like she’d pulled the pin on a cornstarch grenade. I waited for a few seconds for the dust to clear, but then I realized that the reason I couldn’t see anything was that the lenses of my glasses were covered with cornstarch. I took off my glasses (revealing a perfect outline of where they had been), looked down, and realized that there wasn’t an inch of me that wasn’t covered with cornstarch.

Just then, the two boys who had left to fill the measuring cup with water opened the door to the classroom. I turned, and the boys, being greeted by a large powdered ghost and the hysterical shrieks of a dozen laughing kids, nearly dropped the measuring cup and ran.

Chaos ensued. But by the end of class, we managed to get things cleaned up (somewhat) and we were able to recover enough cornstarch from my clothes for a slightly scaled-down version of the original experiment.

As a teacher, I sometimes wonder if the things that I say will be remembered. In most cases, probably not. But I have a feeling that, years from now, in a religion class at BYU, they’ll come to the seventh chapter of Matthew and some kid in the back will raise his hand and say…

“When I was nine, I had this crazy teacher who thought it would be a good idea to illustrate this point with non-Newtonian fluids…”

If that’s the case, the next time we get to this part of the New Testament, I may just pull out all the stops and do this:

Of course, that would work for Matthew 14, too…