La pièce qui réapparaît
A coin hidden by the rim of an empty cup reappears when you pour in water. This simulation recreates that classic demonstration and traces the rays, showing that the coin has not moved — the light reaching your eye has simply been redirected.
Comment utiliser cette simulation
- Fill and empty the container
- Move the coin and the observer's eye position
- Change the liquid's refractive index
Ce qu’il faut observer
- The coin becomes visible only once the liquid is added
- The image sits higher than the coin's true position
- A higher refractive index raises the apparent position further
La physique derrière
Rays leaving the coin bend away from the normal as they exit the water into air. Your eye extends those rays back in straight lines, so the coin appears raised and shifted towards you. The apparent depth is the real depth divided by the refractive index, which is why a pool always looks shallower than it is.