For demonstrating important principles of optics such as reflection by various shapes of mirrors, refraction through several types of lenses, total internal reflection and dispersion.
The apparatus consists of a satin finished metallic disc about 30cm in diameter, graduated around the circumference in 360°. A handle on the back can be used to rotate the disk through 360° in a vertical plane about a horizontal axis perpendicular to the plane and passing through the center of the disk.
The disk is partially shielded by a hood adjustable through 360° degrees. On the hood is a circular plate with slits to allow ray or rays of light to pass and fall on the optical elements. The hood also has a slot for placing red, green and blue filters. The disk face is outlined for various optical elements so that light coming through these slits strikes them at correct angles. The disk is mounted on a heavy tripod base.
A strong source of light for sending parallel rays through the slits and on to the shielding screen is required. Optics and filters are not included.