Students investigate the reflectivity of light as they learn how to make a DIY reflectivity tester out of common everyday items.

GUIDING QUESTION
How does a reflectivity tester work? How can we determine which surfaces are more
reflective?

LEARNING OBJECTIVES
Students will be able to:
• make and use a reflectivity tester.
• identify properties of materials that make them more or less reflective.
• understand and explain how a retro-reflector increases reflectivity.

OVERVIEW
How well light is reflected is an important safety factor. Added reflectivity makes signs more
visible and bicycles and walking clothes safer for their users, especially at night. In this lesson, students make a rudimentary light reflectivity tester to help them determine the relative reflectivity of various materials around the classroom. They determine what qualities make surfaces more or less reflective. As an extension, they are encouraged to learn about retroreflectors and how they are incorporated into 3M safety products. At home, students can
continue to investigate reflectivity with their parents with some simple activities.

Grades 6 – 8