Ending Summer With A Bang

I suppose we all knew it finally had to come to this. The children of Woodland Park have learned to make bombs. Lord help us.

It started innocently enough. We've done it before after all, performing free-form experiments with various liquids (e.g., water, vinegar, corn syrup, vegetable oil) and powders (e.g., flour, baking soda, soap, corn starch).

We made various kinds of sticky dough and lots of fizzy eruptions. This would have been enough to keep Katherine and Lachlan's mom Kimberly, our parent-teacher in charge of the station, busy throughout the morning, but Sherry and Donna had recently posted about their experiments with skewers and re-sealable baggies so I thought I'd throw that idea into the mix as well. The basic concept is to fill the baggies with water, seal them, then pierce them with a skewer. If done just right, the skewer acts as a stopper, preventing the baggie from leaking as the children typically predict. My little twist was that I thought it would be interesting to try liquids of greater density like oil and corn syrup.

I hung out in the experimentation area for a bit, then once the kids had a nice mess going, I broke out the baggies and skewers and demonstrated. There was some interest and surprise, but even though we then made the materials available to the kids, I don't think any of them actually tried that particular experiment. There was some interest, however, in taking the pierced baggies of water and squeezing them in order to shoot streams of water across the table. Se la vie.

With things well under way, I wandered off to other stations, leaving the experimenters to Kimberly.

This final session of summer already had a smaller enrollment at 18 than the classes of 25-26 we ran with during most of the summer, and with a couple kids out sick and a couple more already headed off for long Labor Day camping trips and whatnot, it was a mellow day. There were a couple kids working clay at the art table, a couple using shovels to create a mound of wood chips, a few more in the garden helping Max's mom Callie clean up in preparation for fall, and one or two lazily enjoying their snack. There really wasn't much for me to do, no conflicts to mediate, no emotions to sooth, just a bunch of kids playing with a bunch of moms. A portrait of a cooperative preschool at it's best.

I was in the garden trying to catch more insects to feed to our burgeoning orb spider population, when Lachlan arrived on the scene bearing a sealed baggie that appeared stuffed with some kind of white substance. Upon closer inspection, it was apparent that he had managed to seal his bag around a baking soda and vinegar reaction that was causing the baggie to swell into a tight "pillow" as he called it. Suddenly, without warning, Boom! the seal gave way with a popping sound, spewing the bag's contents onto our just sprouted fall crop peas. Everyone was startled. Lachlan's eyes were wide in amazement.

Oh man, I thought, this is good. While Callie helped Ryan rinse the vinegar off of our sprouts with water from the rain barrel, Lachlan and I returned to the tinkering station with a story to tell and an experiment to try to recreate.

In my head was this vague memory from my own daughter's preschool days of having read about creating a time-release explosive device that involved wrapping a quantity of baking soda in several layers of paper towels, then dropping it into a baggie with vinegar. The idea is that the paper towels delay the chemical reaction long enough for you to seal the bag and move a distance away.

Back in the tinkering area we gave it a try.

We all stood back, watched the bag swell, then after a tension building period, burst open with a Pop! I resealed the bag and recreated the experience again . . .

. . . and again . . .

. . . and again . . .

. . . without adding any more ingredients.

Meanwhile, the children had lost interest in what Teacher Tom was doing, had grabbed their own baggies, and inexplicably had gathered around Kimberly on the ground beside the table to make their own bombs. No paper towel time release mechanism for them, however, instead they discovered that by adding Ivory Snow (a type of natural powdered soap) to their baggies first, the foaming action retarded the chemical reaction enough to give them time to seal their bags.

I'd purchased the inexpensive, store-label baggies. Most of them gave way at the seal, but many burst through the sides, and one resulted in a sudsy arc that Thomas immediately labeled a "geyser."

Before long most of the kids had been attracted by the popping and cheering and we had a veritable minefield in and around our sand pit.

What would happen if we buried one of our bombs in the sand?

The first time we tried it, nothing happened. We unearthed the baggie to find that it hadn't exploded, leading us to conclude that in the effort to slow down the reaction long enough to give us time to bury it, we hadn't added enough explosive material.

So we tried it again. This time with more material and more urgency.

We waited and waited and waited . . .

Well, let's just say we didn't get the sand-scattering explosion we'd hoped for. We did hear the "pop" and the sand did vibrate a bit, but it was an experiment worth attempting nevertheless.

This is why I teach.