UIUC Physics Lecture Demo: Interference: Black Box And Sodium Lamp

UIUC Physics
Lecture Demonstration
Database

Demo # 424

Interference: Black Box And Sodium Lamp

ID # 424

Description:

A sodium lamp illuminates the back of a platform on which two pieces of glass rest. These pieces of glass have a thin layer of air between them. This layer of air is a discontinuity in the index of refraction of the glass, creating visible lines of interference. As the thickness of the layer of air is changed by applying pressure to the glass, the lines of interference shift.

Picture of Interference: Black Box And Sodium Lamp

Physics Concept:

Waves
Interference
Interference Patterns

The demonstration takes about 1 minute to perform.