The Wrong Water Won

The thermometer nailed to the fence said minus nineteen, and Maya's breath came out looking like a cartoon of breath.

"Cold side's the smart side," she said. "Cold water's already closer to freezing. It wins."

Soren was hauling the second bucket up the porch steps, and steam rolled off the top of it into the dark. "This one came out of the hot tap. Dad said don't waste the hot water, so obviously I'm wasting the hot water."

"You're going to lose with that one."

"Probably." He set it down next to Maya's bucket, which she'd filled cold from the garden hose. "But I want to watch it lose."

They were flooding a rink. Two sheets of plywood, a frame of scrap wood, a plastic liner Soren's mom used for the garden. The plan was simple. Pour a thin skin of water across the whole thing, let it set, pour another. Smooth ice by morning if the pours froze fast.

Maya poured her cold bucket along the left half in one careful sweep. Soren poured his steaming bucket along the right, and it hissed and smoked where it hit the freezing liner.

"Left half's going to be skating first," Maya said. "Bet you."

"Bet me what."

"Whoever's water freezes last has to admit the other one was right about water."

"That's the entire bet? Being right about water?"

"There is no bigger bet," said Maya.

They pulled two upside-down buckets to the edge of the porch light and sat. The cold got into Soren's boots. He wrote the start time on the corner of a page, wrote HOT RIGHT and COLD LEFT, and put the notebook back in his coat before his fingers stopped working.

They watched.

The cold left half went glassy at the edges first, a lacy rim creeping in. "See," Maya said. "Head start."

"It's got a head start. It's not winning yet."

The hot right half sat there steaming, dark and liquid, doing nothing a winner would do.

Then it stopped steaming.

Maya leaned forward. "Huh."

"What."

"Your side went quiet." The steam had thinned to nothing. And across the whole right half, all at once, not from the edges but everywhere, the surface had gone from black-wet-shine to a flat gray frost.

"That's not fair," Maya said. "That's the whole sheet at once."

Soren was already on his knees at the frame, tapping. He tapped the left half, Maya's cold half, and it dimpled. Still soft under the crust. He tapped the right. It knocked back at him, solid.

"Yours is soft," he said. "Mine's hard."

"That's wrong."

"I know." He said it happily. "It's completely wrong. The hot one won."

Maya crouched and pressed both palms flat, one on each half, and felt the cold half give and the hot half refuse. She sat back on her heels.

"Do it again," she said. "You did something. You poured different or something."

They did it again. Fresh cold from the hose. Fresh hot from the tap, steaming. Maya poured them this time so Soren couldn't cheat with his pouring. Same result. The hot half beat the cold half, again, the frost slamming across the whole warm sheet while the cold one was still making up its mind at the edges.

"Three times," Soren said, after the third. His nose was running and he didn't care. "I want to know why before I get to five."

"The hot one had less water," Maya said. "Some of it steamed off. Less water freezes faster."

"Maybe. That's a real thing." He wrote it down. LESS WATER? "But look how little steamed off. That can't be the whole win."

"Then the hot water's warmer, so it's moving the heat out faster. Big difference pushes hard." She waved a hand. "Like how a full sink drains faster with more water on top."

"Also maybe." GRADIENT? went in the notebook. "But then cold should still catch up at the end, because it starts closer. And it doesn't."

They both looked at the two half-frozen sheets. Maya's list of things-that-don't-make-sense-yet was getting a new item, and it was sitting right in front of her, glittering under a porch bulb.

"The tap water," Maya said slowly. "Hot pipes. What's different about hot pipes."

"Gases," Soren said. "Hot water holds less dissolved gas. It bubbles out. You see it in a pot before it boils."

"So the hot bucket's got less air in it."

"Maybe that matters. Maybe it doesn't." He underlined GASES and then underlined it again and then stopped. "Maya, I don't actually know which one it is."

"So look it up."

Soren pulled his phone out with two fingers because that was all that still bent. He typed hot water freezes faster than cold. He waited. The screen threw a little rectangle of light onto the frost.

He read for a while. Maya watched his face instead of the screen.

"What," she said. "You've got a face."

"It's got a name," Soren said. "The Mpemba effect. A kid noticed it. In school. Making ice cream. Everybody told him he was wrong."

"Okay. So what's the answer. Is it the gas one or the steam one or the gradient one."

Soren kept reading. Then he looked up, and the porch light caught the frost on his eyebrows.

"That's the thing," he said. "It doesn't say."

"Read the answer part."

"There isn't an answer part. It's real. They've measured it. It doesn't always happen and nobody can say for sure when it will." He turned the phone so she could see. "All the things we said. Evaporation. Dissolved gas. The way the heat moves. Convection. Maybe supercooling. They're on here. As guesses. Grown-up scientist guesses. Still guesses."

Maya took the phone. She read it herself, because she was not going to be right about water on somebody's say-so.

Then she put it face-down on the frozen half so the light went out, and the yard went back to blue dark and stars.

"So nobody won," she said.

"No," said Soren. "Nobody's won yet. That's different."

Maya looked at the two sheets, the soft cold half and the hard hot half, sitting there in a backyard being exactly as strange as they wanted to be, in front of two people and nobody else.

She picked up the hose. "Fill the hot bucket," she said. "We're going to four."

Soren was already carrying it toward the door, steam pouring off the top of it into the cold.