Learn all about thermodynamics with the Crookes Radiometer. When exposed to light or heat, the vanes will spin. This amazing solar windmill is contained in a glass vacuum. 

Just place it near a window and the sales will start to spin. 

It was invented in 1873 by the chemist Sir William Crook and still to this day there is debate on how the sails actually move. 

This solar mill is a fantastic gift for anybody with a fascination in physics.