Ride the Wave

• Teach your students about how Oceanographers use sonar to find objects in the water by showing them how drops of water cause ripples like sonar waves. Fill a clear glass pie pan with water and put on your projector. The water will project onto the screen. Have a student use an eyedropper to drop a single drop of water from 6-inches to the center of the pie pan. The drop will cause ripples the students can see on the projector screen.
  
  

Echoes

• Students can learn how bats use echolocation to judge their position and the position of things around them by learning about echoes. Take your students into a large, empty room and let them make their own echoes. Bats use the sound bouncing off objects back to them to judge how far away something is. This is the same technology that oceanographers use to map the bottom of the ocean. Have students close their eyes and experience an echo blind, like a bat. Have them try echoes in different parts of the room, to see if there is a difference.
  
  

Vibrations

• The vibration of sound is what makes sonar work. Students can experiment with vibration by strumming a rubber band. Give each student a rubber band and have them stretch it between the fingers of one hand and strum it with the other. They will not only hear the sound of the vibration, but feel it against the fingers and see it as they watch the rubber band return to still. Another way to experiment with vibration is to have students place fingers on necks as they make different sounds. Have them yell and whisper to see if there is a difference, or make different vowel sounds.
  
  

Sonar Mapping

• Students can simulate sonar mapping of the ocean floor with a wooden rod standing in for the sonar signal. Have students use clay to make an ocean floor in the bottom of a shoebox and poke holes large enough to insert a thin wood rod through in a centimeter grid on the box lid. Students then exchange boxes and map someone else's ocean floor by poking the rod in each hole, careful not to poke into the clay, and recording the length of rod left on the outside of the box for each hole. These measurements can then be charted to show the topography of the inside of each shoebox ocean floor.