- Shoe box
- thin plastic sheet
- 2-cm x 2-cm (1-in x 1-in.) mirror
- Screen or white surface
- Flashlight or laser
- Open one side of shoe box and cover with plastic sheet tightly.
- Glue the mirror of the center of the plastic sheet.
- Darken the room and have a friend shine a flashlight on the mirror, so the light is reflected onto a screen or wall.
- Speak in a loud voice into the can and observe a reflected light on the wall.
- Make different sound to see what happens.
For Critical thinker:
Hold the drum over the speaker of a stereo while you play music on the stereo and shine a flashlight onto the mirror. Turn the volume up and down. Watch the reflection on the wall. Do you see any difference when the volume changes?
Do you see any different with high notes and bass notes? Try a different musical selection. Try a different stereo if you have another one available. Is there any difference?
Can you think of any other ways to observe vibrations that are caused by sound waves?
When the child shout into a can, the drum head will vibrate, causing the reflected pattern on the wall to change shape. Different sound will caused different shapes. This is a method of changing sound wave into light so they may be observed. It is simple oscilloscope. This principle is used in many technical fields, such as medicine. Musical groups often use this principle to produce light show to company their music.
SKILL: Observing, measuring, predicting, communicating, comparing and contrasting, identifying and controlling, variables, experimenting.
Source: Spangler Science: How to see your voice through a laser