RefractionName: ______

Date: _____Period: ___

Bending of Light

Objective: To develop an understanding of how light will bend as it passes from one medium to another.

Materials: Rectangular prism, optical pins, protractor, pencil, drawing board, and paper.

Discussion: As light passes through transparent (clear) materials, its speed depends on the actual material. For example light travels much faster in air than it does through glass, which are both faster than the speed at which light travels through a diamond. When light strikes a new material head-on, it just slows, if it strikes the new material at an angle, the path of the light ray will bend. Since most materials have constant density, light bending uniformly. This bending of light is called refraction. Refraction is defined as the change in direction of a wave due to a change in speed. Refraction of light is the most common wave refraction, but other waves can bend encountering a boundary.

Procedure:

Pin your paper to the drawing board and trace the rectangular prism as neatly as possible.

Remove the prism and draw a normal line (perpendicular) to one of the longer sides of the prism as shown.

Draw an incident ray that lies at an angle of 20o to the normal as shown. Record the angle of incidence (i) in the provided table.

Replace the prism and place two pins, pin 1 and pin 2, on the incident ray and keep them spaced at least 5 cm apart.

View pin 1 and pin 2THROUGH the prism (ignore the location of the actual pins). Take pin 3 and block images of pin 1 and pin 2out.

Again, viewing THROUGH the prism, block the image of pin 1, pin 2 and the actual pin 3 out with pin 4.

Remove the prism and use pin 3 and pin 4 to construct the emergent ray. The emergent ray should start at the edge of the prism.

Connect the incident and emergent rays to form the refracted ray

Record the angle that the refracted ray makes with the normal (r)

Repeat for incident angles (i) of 30o, 40o, 50o, and 60o

Make sure to label your diagram. Once you are complete, attach it to this lab sheet.

Data:

Table 1.

Trial / i (o) / r (o) / Observations

Closure:Complete these questions with your lab group.

  1. In this experiment, light bent as it encountered a boundary between two mediums. What is this called?
  1. Do you notice any uniformity in how rays of light were bent as they passed through glass?
  1. How would the angles of refraction change if instead of a glass prism, a diamond prism were used instead? Explain.
  1. What are some everyday examples of bending of light? Give at least three examples?