Newton's ring apparatus consists of a Plano-convex lens mounted on an optically plane glass plate.
This entire assembly is mounted in a circular heavy duty metal frame.
The pressure between the plates can be adjusted by three brass plated nickel screws.
This simple apparatus nicely demonstrates Newton's rings, which are created by the reflection of light between two surfaces, and forms for one of the basic experiments at graduation level.
When viewed under monochromatic light, students can observe how these rings appear as a series of concentric, alternating bright and dark rings centered at the point of contact between the two surfaces.
Also students can appreciate a concentric ring pattern of rainbow colors, when viewed under white light.