On Monday Dave, not feeling well, decided to stay home. I took advantage of the situation to run a pesky errand — one of those that ought to be done during the week, but would be so much easier without children along.
I walked back into the house to find Dave standing beside the kitchen sink, with a strangely dark puddle hissing and steaming on the floor beside him.
“Do we have any more baking soda?” he asked by way of greeting.
“Uh… I don’t know,” I said, cleverly.
“Could you check? Also you might open some windows. I’m going to take a shower.” He was already stripping off his shirt as he spoke.
“There’s molten aluminum on the floor!” Nathan told me excitedly.
“No, it isn’t molten,” said Dave as he disappeared around the corner.
By now anyone with chemistry experience will have grasped the gist of what happened, so after discovering that we had no more baking soda in the house, I grabbed the baby and made a quick run to the store. Small box for the baking cupboard, big box for the chemical cupboard. (“For a Fresher, Cleaner Home” the box assured me.)
Once I got back and the acid had been neutralized, we had plenty of time to discuss the details while we worked on cleanup.
It seemed that Dave had gotten out the hydrochloric acid (yes, ours is the sort of household that just keeps that around) for a little cleanup job, and had decided to give the boys a chemistry demonstration. Aluminum and hydrochloric acid will react and give off hydrogen gas; done correctly, in a bottle, one can capture the gas in a balloon. This not only is a cool demonstration of a chemical reaction between solid and liquid producing a gas, but you end up with a balloon filled with a highly flammable gas that you can then explode. Win-win!
The trouble, Dave explained as we wiped baking soda and aluminum off the floor, was that he hadn’t spent enough time on preparation. After all, it isn’t as though he hasn’t done this sort of thing before — but he wasn’t careful with the amounts, and added way too much, so that neither component was limiting. He also hadn’t made sure to have the baking soda at hand. And worst of all, when he realized how quickly the reaction was going and the plastic bottle was heating up, he went to remove the balloon, but in doing so tilted the bottle. Hot liquid ran into the balloon, which subsequently exploded. It was only a minute later that I walked in.
Dave got a couple of very minor burns, probably from hot flakes of aluminum landing on his hands. The baby was well away of course, and the boys (Dave informed me) exhibited really excellent self-preservation skills and scattered as soon as they realized something was not right.
And I would just like to sum up by pointing out that we live in a really cool house. And also that we should always keep large amounts of baking soda on hand.