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Oct 23

Cornstarch and water speaker experiment in STEM testable question science

The girls were so excited to enter the classroom and see sound equipment. They instantly began to guess what we would be doing for the day- they had lots of predictions.

I told them how we would be continuing our sound/vibration study today by finding another way to observe it- with a speaker. Luckily for me, my husband knows a lot about sound equipment, and he volunteered to come in and help with the experiment. I also know when a topic is above my expertise and I need to recruit someone. Win/win! We took some time to mix the corn starch and water together.

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Next we talked about how sound waves look, the range of frequencies of sound, and decibels.

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We showed them a cool app that showed them where their voice fell in the range of frequencies. They were eager to talk into the iPad and giggled as they raised and lowered their voices. The range of frequency is measured in hertz.

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We then went to see what the cornstarch and water would do if we increased the hertz. We started low and slowly moved it higher. It was very cool to see it start to move.

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We then wanted to see if their voice could move the corn starch- we plugged a microphone into the speaker and let them try. No luck- their voices didn’t generate the right frequency or enough decibels.

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Then, we decided to see what would happen if we played music. We started with this song:

We also let them select a couple of songs. “Timber” did not have a wide enough range of frequencies, but “turn down for what” wasn’t too bad.

We ended our time letting the girls build to music. A very cool afternoon!

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