Crookes radiometer
Radiómetro de Crookes
- Date
- 1873 · confidence high
- Place
- London, United Kingdom
- Credited to
- William Crookes
- Field
- Knowledge & symbols
What it is
A partially evacuated glass bulb with vanes that rotate when exposed to light, spinning faster with more intense light; it provides a qualitative measure of electromagnetic radiation.
Discovered by chance by Crookes while weighing chemical samples in a partially evacuated chamber; the correct explanation for its spin was not established until 1879.
What it led to
- Scientific debate over radiation pressure
- Educational use as a demonstration of a light-driven heat engine