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!

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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.

Connections with Next Generation Science Standards (NGSS)

Waves and Their Applications in Technologies for Information Transfer MS-PS4-2.

Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.

Demonstrate that sound waves can transfer energy and cause objects to vibrate or move