Low Cost Demonstrations In Optics Created by Alyssa

Low Cost Demonstrations In Optics Created by Alyssa Cederman and Jessie Segal Advisor: Dan Mac. Isaac Organization: EURP Buffalo State College Department of Physics

Purpose • Traditional optics demonstrations are expensive and difficult or impossible for physics teachers to construct. • Our goal was to convey physics concepts visually with very little cost and time required in constructing apparatus using a modern green laser diode.

Low Cost Poisson’s (Arago’s) Spot Apparatus

Poisson's (Arago’s) Spot • A map pin in a laser beam causes diffraction patterns. The resulting patterns are a bright spot in the center of the shadow and surrounding internal rings. • The map pin can be replaced with other small objects for different diffraction patterns.

Low Cost Variation of Young’s Double Slit Apparatus

Diffraction with Hair or Wire • Light bends around a hair and causes diffraction patterns. The distance to the fringes from the center (yn) can be calculated with: http: //en. wikipedia. org/wiki/Interference And for dark fringes:

Low Cost Apparatus for Varying Index of Refraction

Varying Index of Refraction Using Sugar Solution • The sugar solution bends the laser light, and the mirror reflects the light. • The laser beam bends due to the varying index of refraction. • Refraction can be calculated by using Snell’s Law:

Apparatus for Total Internal Reflection (TIR)

Total Internal Reflection (TIR) Using a Soda Bottle • The critical angle is found by a modification of Snell’s Law:

Apparatus for Newton’s Rings

Newton’s Rings Using Microscope Slides • The angle between two microscope slides can be found by using Newton’s Rings with the math below:

Conclusions • Optics demonstrations can be created using common household items and office supplies. • Green lasers are now cheap, and they produce much brighter results compared to red He. Ne or diode lasers or expensive sodium light sources.