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Let’s make a sandwich!
We’re not talking about a sandwich you can eat for lunch, but rather a sandwich that makes beautiful sound! In this Saturday Science experiment from Exploratorium, discover how small adjustments to vibrations can raise or lower the pitch of sound.
Materials
- 2 jumbo craft sticks
- 1 straw
- 1 wide rubber band
- 2 smaller, thin rubber bands
- Scissors
Process
- Wrap your wide rubber band lengthwise around one of your jumbo craft sticks.
- Use the scissors to cut two 1-inch pieces of straw.
- Put one of the small straw pieces underneath the wide rubber band, about a third of the way down from the end of the stick.
- Take the other craft stick and place it on top of the first one.
- On the same side where you placed the straw piece, wrap one of your thin rubber bands around the end of the sticks, about a half an inch from the edge. The rubber band should pinch the two craft sticks together.
- Put the other small piece of straw in between the two craft sticks, about a third of the way down from the end of the stick. Don’t put the straw underneath the wide rubber band this time.
- Now, wrap your other thin rubber band around this end of the craft sticks, about a half an inch from the end. There should be a small space between the two craft sticks created by the two pieces of straw.
- Put your lips against one of the long edges of the craft sticks, between the small straws, and blow through the sticks! Did you make a sound?
- Move the straws closer together. Does the sound change?
Summary
When you blow into the Sound Sandwich, you make the large rubber bands vibrate, and that vibration produces the sound. Think back to the straw flute we made last week: different vibrations create different sounds. Long, massive objects vibrate slowly and produce a low-pitched sound, while shorter, less massive objects vibrate quickly and produce a high-pitched sound. When you moved the straws closer together, you shortened the part of the rubber bands that can vibrate, so the pitch is higher than the pitch of the original sound. If you watch closely when someone else is playing the sound sandwich, you can watch the rubber band vibrate!
Want more Saturday Science? See all of our at-home activities on the blog or on Pinterest.
