Here are some videos to watch, after they've worked on the Patterns Page for 30 minutes (they should have it, extra copies on desk):
Echolocation and parts of the wave:
Dolphins
Echolocation and Doppler Effect
Boy who can Echolocate
Then they can complete the echolocation part of the page
Then the Ultrasound video here and they can work on the ultrasound
Ultrasound Video
