Two Volcanoes

Talia worked on her volcano for two weeks. She built it from paper and glue and painted it grey and brown, with a little green forest around the bottom. Diego made his on Sunday night from a plastic bottle and a cardboard box.

At the science fair at Bell Street School, every project needed a card with three words on it: question, process, result. The two volcanoes stood on the same table.

Talia poured her vinegar in first. The red bubbles came up, ran over the paint, and stopped. Three seconds.

Then Diego poured his in. The bubbles went straight up out of the bottle and kept coming for almost half a minute. Some of them reached the floor.

“Why is yours better?” Talia asked. She wasn't angry, only interested.

Diego looked at the two volcanoes. “Because the top of mine is small, I think. Yours is a wide dish, so everything gets out at once.”

Talia opened her notebook and wrote her result: a narrow top gives longer bubbles than a wide dish.

“You can copy my bottle next year,” Diego said.

“And you can copy my paint,” she said.