- Have all the students cut the neck off the balloon with scissors and then stretch it over one end of the can until it's flat. Pull two elastic band over it so the balloon will stay in place. Also tape the edge of the balloon to the can for extra measure.
- Glue the piece of mirror (face out) to the stretched balloon about a third of the way in from the edge of the can.
- As students finish making their sound viewers, ask them to come up one by one to a table that is set up near a white wall (or a white paper covered part of the wall).
- Have them lay the can on its side on the table, with the balloon facing the wall.
- Teacher shines the flashlight onto the mirror at an angle so you can see a bright spot from the mirror reflected on the wall as shown below.
- Ask student to sing our shout into the open end of the sound viewer. Watch the spot on the wall. What happens?
(The spot of light on the wall should vibrate because when the sound waves from the student's voice hits the balloon, it makes the balloon vibrate. Then, this causes the mirror and the light reflecting from it to vibrate too.)