Ever wondered if you can see sound? Well, in this experiment, you’ll use a Ziploc® brand sandwich bag to turn music into motion. It works because sound is a wave: a vibration that travels through the air (or another material) like a wave travels through water. Normally, we only hear these vibrations, and we can't see them. But by using the vibrations to make sprinkles dance, you’ll be able to see sound waves!
Stretch the plastic wrap across the top of the bowl. Make it as tight as you can, with as few wrinkles in the wrap as possible.
Pour some sprinkles into a Ziploc® brand sandwich bag. Then seal the bag, leaving a pocket of air, so the sprinkles have room to dance!
Place the bag on top of the plastic wrap on the bowl.
Using your device, find different songs and turn up the volume to watch the sprinkles dance. For best results, download a tone generator and see what happens when you play.
Any vibrating thing (like a speaker) will make a sound. As the speaker vibrates and creates sound, it pushes the air around it, setting up a vibration in the air —that’s a sound wave! In this experiment, the vibrations move through the plastic wrap, pushing and shoving the sprinkles around. As the tones change, the vibrations change, and the sprinkles move as if they are dancing. You’ll see the sprinkles move away from where the vibrations are the strongest. To observe what happens to the sprinkles when you play a single sustained note, link your device to a tone generator. A pure tone will create a consistent, unchanging vibration in the plastic. Instead of dancing around, the sprinkles should collect in places where the plastic isn’t vibrating, making patterns that depend on the frequency of the pure tone.
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