# Optics: Laser Light Show

In this lab, you will explore the behavior of light. You will observe reflection and refraction of a laser beam in jello, and use a diffraction pattern to measure the width of a hair.

Teacher Version

###### Recommended Prerequisites:
• Basic Lab: protractor use, basic calculator arithmetic
• Advanced Lab: protractor use, basic calculator arithmetic, basic trigonometry (sin and sin-1 with a calculator)
###### Key Concepts:
• Light always travels in a straight line except when it interacts with an object through reflection, refraction, or diffraction
• Reflection occurs when a light wave hits an obstacle (eg: a mirror) and bounces back (reflects).
• Some obstacles (eg: glass, water) allow light to pass through, but slow it down. In this case, the light ray bends as it crosses the object boundary. This is known as refraction. The angle of refraction depends on the speed of light in the object.
• Light waves can bend around a small obstacle or when passing through a narrow slit. Light waves generated by points around the obstacle overlap to create patterns of light and dark bands. This process is known as diffraction.