All that was left of the Dr Pepper can was a shrivelled twist of metal. It was hot to the touch. Spookie picked it up with pliers and dropped it in a metal bucket of cold water. She took the bucket up to their bedroom. As an afterthought she stood it on four bathroom tiles placed on a heavy metal tray, resting on Dyspepsia’s desk, which was itself all-metal.

In the morning the windows were steamy. There was no water in the bucket, which was hot enough to burn your fingers. The tiles it was standing on were hot. The tray the tiles were standing on was hot. The metal desk was hot.

“It should have cooled down by now,” said Dyspepsia. She thought of the Sun, and how it hadn’t cooled down in four-and-a-half billion years. “Hey!” she said. “Do you suppose we’ve made thermonuclear energy?”

Spookie wrinkled her nose, which made her whiskers go funny. “No way,” she said. “The shrivelled can would have melted. It would have vaporised! Anyway, there’s no way a thermonuclear reaction could have been sustained.”

Dyspepsia didn’t know what “sustained” meant. She’d thought she’d look it up later when Spookie wasn’t around.

Spookie got more water in a big jug and poured it into the bucket. There was a huge hiss and a lot of bubbling, plus a lot of steam. As the bubbling died away, Spookie peered in the bucket. She saw a tiny spark come out of the shrivelled can and float to the top, in its own little bubble. When it got to the top the bubble went pop! and the spark sank again. But soon it floated up in a fresh bubble, which went pop!—and so on, and so on. It was fun to watch.

Spookie got a little bottle made of clear glass. It had its own tiny cork, which she stuffed in the neck when she’d caught the spark. Then she put it on the desk and watched the spark going up-and-down, up-and-down, inside the bottle. In an hour’s time the bucket was quite cold. But the tiny bottle stayed warm. Not too warm, though. Not enough to boil the water and pop the cork. Heat was escaping faster than it had from the bucket.

Every now and then Spookie gave the bottle a tap to stop the spark settling on the bottom. She felt that if it did so, it would get snuffed out. The water didn’t put it out because it was making itself a little jacket of steam inside its bubble. Glass was a different matter.

Dyspepsia thought the spark was fun, in its tiny bottle. She was going to take it to school, so she could look at it during the day and keep it well-tapped to stop it getting snuffed out.

But something was troubling Spookie. She kept shaking her head and muttering to herself “That’s Hawking radiation, or I’m a dog!”

…to be continued.