# Investigating the Photoelectric Effect and Electronic Light Sensors Kit

Determining Planck's Constant with LEDs: Investigating the Photoelectric Effect and Electronic Light Sensors Kit

In 3 experiments, students determine the wavelength of 4 LED colors and construct a circuit to find the threshold voltage of the LEDs. This is used to calculate frequency and energy, and to generate a mathematical model for Planck's constant.

Take a smartphone selfie, walk through an automatic door, or turn on your television with a remote, and you're using light sensors based on the photoelectric effect.

In this comprehensive kit students:

- Investigate light sensors and the photelectric effect
- Build circuits to determine Planck's constant
- Learn how light-emitting diodes (LEDs) and transistors function

Students establish relationships among light frequency, wavelength, and energy for LEDs while collecting data to calculate Planck's constant. Investigate the wave and particle models of light as students calculate threshold voltages to turn on LEDs (photoelectric effect) and calculate wavelength using a diffraction grating. The photoelectric effect and the discrete nature of quantum mechanics are addressed, laying the foundation for this lab.

Activities are designed for 4 groups working in 4 student teams. FREE 1-year access to digital resources that support 3-dimensional instruction for NGSS included.