Colour by Reflection vs Colour by Temperature

This simulation demonstrates the difference between colour observed from reflected light and colour emitted due to an object's temperature. It visualises Kirchhoff's law: at thermal equilibrium an object's emissivity equals its absorptivity, so a hot object radiates the same colour as its surroundings.

Students step through five stages using numbered buttons and can change the lamp colour (off, white, red, green, blue) and the oven temperature via the control panel. They watch a grey stone, blue ball, red brick, and blue cone change colour under various lighting and heating conditions, eventually all merging into the same glow as the walls.

By interacting with the simulation, learners see how selective reflection works, how thermal radiation overtakes reflected light at high temperatures, and how objects approach black‑body behaviour. The activity reinforces concepts of emissivity, absorptivity, and the relationship between temperature and emitted colour.