Student Exploration: Refraction

Vocabulary: angle of incidence, angle of refraction, frequency, index of refraction, medium, refraction, Snell’s law, total internal reflection, wave front, wavelength, wave speed Prior Knowledge Questions (Do these BEFORE using the Gizmo.) Two runners ran side by side, each holding one end of a horizontal pole. 1. What would most likely happen if one of the runners began jogging in knee-deep water? The jogger who was running in the water probably slow down. How would this affect the direction of the runners? Explain. This would affect the direction of the runner because the runner would try to run forward, but the runner would end up slipping and most likely falling backwards. 2. Gizmo Warm-up Light can travel through many materials, or media. As with a runner on pavement or sand, the speed of light can change when it moves into a different medium. The Refraction Gizmo™ allows you to observe what happens to a beam of light as it travels from one medium to another. Turn off View wave fronts. Set Index of refraction 2 to 3.0. 1. Click Play ( ). Observe the ray of light as it passes from Medium 1 to Medium 2. A. What happens to the speed of the light wave? The speed of the light wave stayed the same B. What happens to the direction of the light wave? The direction of the light turned to a 90 degree angle. The bending of the light ray you see is called refraction. 2. Click Reset ( ) and turn on View wave fronts. A wave front is an imaginary line that connects the crests or troughs of a wave. The wavelength of a wave is the distance between wave fronts. Click Play. What happens to the wavelength of the wave as it passes into Medium 2? The wavelength still changed into a 90 degree angle