Back home, she opened her textbook. The diagrams were no longer confusing scribbles. They were maps of the lighthouse. The formulas were no longer abstract symbols. They were the language of how things work .

“Sound needs a medium,” Grandfather said, putting the fork in a vacuum jar. The sound died.

Anya was scared. “It’s poisonous.”

Anya looked at her grandfather. She hadn’t memorized formulas. She had lived them.

She powered the coil. It became a magnet, repelling the permanent magnet, and the motor jerked to life. This was the : a current-carrying wire in a magnetic field experiences a force .

“How do we get this heavy trolley moving?” Anya asked.