Faraday Rotation was the first experimental evidence that light and electromagnetism are related. In this demonstration, an electromagnet is used to create a magnetic field that is parallel to a beam of light in water. Although water by itself has no effect on light polarization, with the magnetic field it rotates the polarization by an amount that is proportional to the strength of the magnetic field.
Specifications for this demonstration:
Two coils of wire: 570 turns, 6 cm inner diameter, 15 cm length
A current of 6.5 A produced approximately 2 – 3 degrees of rotation in either direction. This rotation was clearly visible using medium quality polarizers (https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=4984).
