The radiometer was invented in the 1870s by British physicist William Crookes as an experimental instrument that converts light energy into kinetic energy. The speed of rotation changes depending on the intensity of light and the light source. If you place it near a window where light comes in or near an incandescent lamp, you can enjoy the movement of the wings as an interior.

Size package: Width 9.9 x Height 20.9 x Depth 9.9 (cm)
Size radiometer: Body / Ф8.0 x Height 16.0 (cm)
Material: Glass
Package: In a paper box

Notes

-Since this product is handmade, there are individual differences such as slight scratches, chips, shape and size.
-It rotates when exposed to light rays containing infrared rays (heat rays) such as sunlight and incandescent lamps, but there is no reaction when there is little light such as fluorescent lamps and LEDs.
-In rare cases, the black paint on the metal plate inside the glass ball may peel off. Please note that there is no problem with the quality of the product.