Observations and results
Moving air flowing over the rubber band makes it vibrate the same way wind blowing over a flag makes it wave. These vibrations produce sound, like the strings on a guitar do. As the rubber band vibrates, it shakes the entire contraption including the index card. Because the vibrating index card moves along with the rubber band but pushes a lot more air than the latter it amplifies the sound. Did you find ways to change the pitch of your contraption's sound?
More to Explore
Ear Guitar, from Exploratorium
Sound Facts, from Science Kids
What Makes a Bee Buzz?, from Highlights Kids
Accidental Scientist: Music, from Exploratorium
“Buzz Like a Bee” was developed by Exploratorium and is on page 80 of Exploralab. Created by Exploratorium, “Exploralab: 150 Ways to Investigate the Amazing Science All around You” is a book that takes curious kid scientists, ages eight to 12, through 24 hours' worth of household investigations, experiments and discoveries.
This activity brought to you in partnership with Exploratorium