Sound travels in waves, similar to light. If you shine a light onto a mirror the light bounces off the mirror so that the light shines in a different direction. The same is true for sound. Sound waves can reflect off of surfaces, redirecting the waves creating an echo. A gymnasium is a good example of how echoes are produced. The room is large with six hard surfaces, the four walls, floor, and ceiling. A few seconds after you yell you can hear it again because the sound waves bounced off of the six surfaces and back to your ear. In this experiment students will create echoes by yelling in spaces, such as an empty room, gymnasium, and bedroom.
Students will explore how sound waves are reflected and absorbed by producing echoes.
Find locations where you can produce an echo:
- Dance hall
- Banquet hall
- Choose at least three locations to produce your echoes. You should choose at least two, large rooms that are empty and a large room filled with furniture.
- Stand at one end of the room and yell out, “Hello”. You can yell out whatever you would like.
- Did you hear an echo?
- Repeat for the remaining locations.
- What was different about the rooms that produced an echo and those that did not?