Product 12531

Product Details

The discovery of the photoelectric effect opened the door to understanding electron structure. Explaining how it proves the “quantum” energy of light has never been easy—until now! Demonstrate the photoelectric effect using a zinc plate attached to a charged electroscope. Simply charge the electroscope negatively using a rubber rod, and then shine short-wavelength UV light from the Sun or a lamp onto the zinc surface. Electrons given off by the zinc metal cause the electroscope “leaves” to collapse as the negative charge on the electroscope is neutralized by the resulting positive charge on the zinc. If the light is below the minimum threshold energy, the electroscope will not discharge regardless of how bright the light source. An economical way to bring the excitement of the quantum age into your classroom! Teacher Demonstration Notes included.

Concepts: Photoelectric effect, energy and wavelength of light, quantization of energy.
Time Required: 20 minutes
Note: The demonstration may be performed outdoors using ultraviolet light from the Sun. Performing the demonstration indoors requires a short-wavelength UV lamp, which is available separately.