Follow light and vibration into the body. Separate the physical signal from the work of sensing and perception.
Interactive explorationOpen a sourced 3D eye, move a target nearer, and catch the moment its light comes together. Then discover why a smaller pupil is different from better focus.
Interactive explorationStart with a vibration. Follow air, eardrum, tiny bones and hair cells, then see why the message reaching your brain is a different kind of signal.
Interactive explorationNudge a membrane, discover when a spike appears, test its recovery, and cross a chemical synapse. Then inspect a real potassium-channel structure.
Interactive explorationChange a fictional sleep history, catch the moment two curves meet, and separate a local clock change from a biological clock. Then follow light information from eye to brain.
Slide an object toward a lens. Follow the rays, find a sharp image, and discover the moment a camera becomes a magnifier.
Take these steps at your own pace. Your place is not saved as account progress or scored.