The goal of this activity is for students to observe wave interference, identify variables that affect the characteristics of the interference, and determine the relationship between these variables and these characteristics.

In the Preliminary Observations students will observe a diffraction pattern in light or sound. They will identify several factors that they think may influence the diffraction pattern and select one to investigate using a Vernier Diffraction Apparatus. Since groups may be investigating different factors, you will need a class discussion after the investigations to summarize the class’s findings.


  • Design and perform an investigation.
  • Draw a conclusion from evidence.
  • Understand how the principle of wave interference can create the series of bright and dark spots that form diffraction patterns.
  • Develop a model that relates at least one variable that affects interference or diffraction patterns.