Observe the square wave above. This is a copy of a real sonar ranger graph. Discuss with your partner(s) how to reproduce this type of wave. What motion must you make with the box? Do you notice anything about differences or similarities in the direction or speed of the box when making a square or curved wave? Note the slight changes in the graph due to sideways movement or shaking of the box. Maybe you can do better!

When you are sure of your method, use the flat box in front of the sonar ranger to make the square 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 show one distance-time graph display. Refer to Technical Hints to run the sonar ranger software. Repeat until you capture a square wave. Let your partner(s) also try to make the square wave. Print out the best graph. Refer to Technical Hints to see how to print a graph.

Discuss with your partners how to make wider and slimmer square waves. Test it out!