Clear Icicle Light Mill Christmas Ornament

£40.00

The light mill, consists of an airtight glass bulb, containing a partial vacuum. Inside are a set of vanes which are mounted on a spindle. The vanes rotate when exposed to light, with faster rotation for more intense light, providing a quantitative measurement of electromagnetic radiation intensity.

This ornament will spin when exposed to direct sunlight or artificial light. At night the light mill will sit still.