PhysicsLAB: Refraction of Light

Refer to the following information for the next two questions.

A pair of toy cart wheels are rolled obliquely from a smooth surface onto two plots of grass - a rectangular plot as shown at the left, and a triangular plot as shown at the right. The ground is on a slight incline so that after slowing down in the grass, the wheels speed up again when emerging on the smooth surface.

Discuss with your partner the path and direction of travel for each cart. You need to finish each sketch on a sheet of paper. Be sure to show the orientation of the wheels inside the plots and on the other side.

Describe the cart's path through the rectangular plot.

Describe the cart's path through the triangular plot.

Refer to the following information for the next question.

Red, green, and blue rays of light are Incident upon a glass prism as shown below. The average speed of red light in the glass is less than in air, so the red ray is refracted. When it emerges into the air it regains its original speed and travels in the direction shown. Green light takes longer to get through the glass. Because of its slower speed it is refracted as shown. Blue light travels even slower in glass.

Discuss with your partner the path and direction of travel of the blue ray.

Refer to the following information for the next question.

Below we consider a prism-shaped hole in a piece of glass - that is, an "air prism."

Discuss with your partner the path and direction of travel of the beams of red, green, and blue light as they pass through this "prism" and back into the glass.

Refer to the following information for the next question.

Light of different colors diverges when emerging from a prism. Newton showed that with a second prism he could make the diverging beams become parallel again.

Which placement of the second prism will do this?

Refer to the following information for the next four questions.

The sketch shows that due to refraction, the man sees the fish closer to the water surface than it actually is.

Discuss with your partner the direction a ray beginning at the fish's eye would follow to show the fish's line of sight when it looks upward at 50° to the normal at the water surface. The critical angle for a water-air interface is 48º.

At the 50° angle, does the fish see the man, or does it see the reflected view of the starfish at the bottom of the pond? Explain.

To see the man, should the fish look higher or lower than the 50° path?

higherlower

If the fish's eye were barely above the water surface, it would see the world above in a 180° view, horizon to horizon. The fish-eye view of the world above as seen beneath the water, however, is very different. Due to the 48° critical angle of water, the fish sees a normally 180° horizon-to-horizon view compressed within an angle of