A beam of light can pass into and out of a block of material fairly easily if the block has parallel sides. If the angle of incidenve is 0, the angle of refraction is 0 and the ray passes straight through. If the ray makes an angle with the normal line that is not equal 0, the ray passes through the material and emerges on the far side parallel to the original ray but shifted over some small distance.

The problem becomes more difficult with one side of the material is flat and the other side is something else, say, semicircular in design. See the diagram at left It shows the ray coming in from the bottom and striking the flat surface with the angle of incidence equals 0. This ray passes through undeflected. Soon however it encounters the other surface. The dotted line that you see represents a normal line (Tell why it is a normal line) Your task is to find the measure of the angle that the ray of light makes with normal line has it exits the tank. Three meters beyond the tank is a wall with the dry erase board. Place a dot where you think the laser beam is going to hit. I will then shine the laser beam along the path that you suggest and see where emerges from the tank to strike wall.

Your team score will be determined by the distance from where you predicted the light would strike the wall to where the beam was incident, measured to the nearest centimeter.

Your score for this event will be 60 points if you hit the wall plus 40 points times the shortest distance for missing the target divided by your distance.

Last edited 01/01/06