Observe the triangular wave above. This is a copy of a real sonar ranger graph. Discuss with your partner(s) how to reproduce this type of wave. This one is tough. You may choose to use the ceiling instead of the box for reflection. What motion must you make with the box? Do you need to change the direction or speed suddenly? Again, note the slight variations in the graph due to a sideways movement of the box.

When you are sure of your method, use the flat box in front of the sonar ranger to make the triangular wave. Stand approximately 1 meter away from the sonar ranger while your partner directs the detector at the box. Move the box back and forth to produce your wave while using the sonar ranger software on the computer. Make sure that the sonar ranger software is set to one distance-time graph display. Refer to Technical Hints to run the sonar ranger software. Repeat until you capture a triangular wave. Let your partner(s) also try to make the triangular wave. Print out the best graph. Refer to Technical Hints to see how to print a graph.

Discuss with your partners how to make a greater or fewer number of triangular waves. Test it out!