Noun
electromagnetic radiometer consisting of a small paddlewheel that rotates when placed in daylight
Source: WordNetThe Crookes radiometer turns when the MFP is larger than the size of the vanes. Source: Internet
The first experiment to test this theory was done by Arthur Schuster in 1876, who observed that there was a force on the glass bulb of the Crookes radiometer that was in the opposite direction to the rotation of the vanes. Source: Internet