# Change in Wave Speed & Wave Refraction Lab

(this experiment is to be used with the Waves program from SPECS)
Wave Speed

Step 1: Create a wall with width 150, height 350 and place it in the middle of the window. Set the frequency to 20, and the index of refraction to 50.

Step 2: Run the program and observe the behavior of the wave as it passes through the barrier. To make it easier to see you might want to place the cursor at the point where the wave and wall meet.

Recall the wave equation

Are the waves traveling faster or slower as they pass over or through the wall?

The waves before the wall are traveling in one medium, while the waves going through the wall are traveling in another.

Do your observations suggest that waves travel at the same speed in all media? Based on your observations do you think that sound travels at the same speed in steel as in air or that light travels the same speed in air as in glass? Why or why not?

Step 3: Now place the wall against the left hand side of the window. Make the wall high enough to go all the way across the window. Run the program.

How are the waves different in this case ?

Wave Refraction

Step 4: Use the same set-up as before (step 1 above), except change the rotation of the wall to 25.

Step 5: Run the program an observe the wave and graph patterns.

Do the waves bend toward or away from the normal when they leave the wall?