“Foundations should be true ,” she said. “Otherwise they’re just fossils.”

“Was it incorrect?” asked Elizabeth.

“It is exactly the point. Mr. Filmore claimed that a solid has a fixed shape and a liquid takes the shape of its container. That’s true for a brick. It is not true for sodium, which is a solid but can be cut with a butter knife. And it is certainly not true for pitch—a solid that flows so slowly it takes a decade to form a single drop.” She placed the pie on his desk. “Madeline was correcting a category error. You punished her for accuracy.”

The meeting ended predictably—with Elizabeth being asked to leave and Madeline receiving an in-school suspension. But on the way out, Elizabeth paused at the classroom door. Mr. Filmore was at his desk, grading worksheets. He looked up, startled.

“No,” she said. “But here’s a lesson they won’t teach you in school: being right is not the same as being safe. And being quiet is not the same as being wrong.”

“Mrs. Zott,” said the principal, Mr. Hendershot, a man whose tie was perpetually askew, as if even his wardrobe had given up on him. “We discussed this on the phone. Madeline interrupted class to tell Mr. Filmore that his explanation of ‘solids and liquids’ was—and I quote—‘ontologically lazy.’”

She handed Mad a notebook. On the first page, Elizabeth had written: Properties of Sodium: Soft. Reactive. Dangerous if provoked.

“Mr. Filmore,” she said. “Does your curriculum include thermodynamics?”

That night, Mad sat at the kitchen table, holding a frozen bag of peas to her eye. “Was I wrong to correct him?”