He remembered his grandfather, an engineer who used to say that physics wasn't about numbers, but about how the world "breathes."

He picked up his phone and typed back to the group: “Don't use the GDZ. Masha, check your signs on the work equation. The gas is expanding, so the work is positive.”

He closed the Nikolaev book. For the first time all semester, the gatekeeper had let him through.

Ivan hovered his thumb over the screen. The "GDZ" was a siren song. It was the easy way out—a neat, pre-packaged explanation that would satisfy the teacher tomorrow morning. But as he looked back at the diagram of the piston in his book, a spark of stubbornness flickered.

He sighed, his phone buzzing with a notification from the class group chat. “Did anyone get problem 4? I’ve tried three times and I keep getting a negative Kelvin temperature,” Masha had messaged. “Check the GDZ (Ready Homework Solutions),” someone replied instantly with a link.

Ivan put the phone face down. He re-read the paragraph, not as a chore, but as a map. He traced the logic: if the pressure stays the same and the volume grows, the gas must be pushing against the world. It was doing work . Slowly, the abstract symbols began to shift.