A question to carry with you

Guided reading paths

Move from a first encounter to the instruments and back to the complete paper. Each stop tells you what to try, what to question, and where to go next.

Choose a route, not a difficulty level. Start with the no-algebra entrance, skip to any stop, or spend as long as you need in a laboratory. No score, timer, account or saved answer is required.

These paths lead through an edition that is still in preparation, and following one is not a sign that anything on it has been reviewed. Each page a path reaches says what it shows and where it stops.

From wandering to a molecular number

Choose what to measure, explain a growing spread, then ask what the observations can actually identify.

7 stops · Read, experiment and explain

From entropy to energy packets

Preserve the successes of waves, examine a restricted entropy comparison, and distinguish a hypothesis from its consequences.

8 stops · Read, experiment and explain

Clocks, coordinate maps and light

Define a measurement before transforming it, then carry the same discipline into the electrodynamic half of the paper.

8 stops · Read, experiment and explain

Two ledgers, one inference

Follow a symmetric emission, subtract two descriptions, and distinguish a derivation from a consistency check.

6 stops · Read, experiment and explain

Take a detour without losing the question

On a guided page, the navigation above the content offers the previous stop, next stop and full outline. A bookmark link saves only the public reading position. It does not save your laboratory settings, notebook or predictions.

Without JavaScript, every outline, task, explanation and destination link remains readable. Return with your browser's Back command after visiting a stop, or keep the outline open beside the paper.

Explore the longer discovery reconstructions · Choose an instrument directly