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science surprises
photo of mariko with a plastic strip talking strip!
A simple long, thin strip of plastic has a series of ridges along one side. Pull the strip through your thumb and index finger, with your finger nail edge running over the tops of the ridges. You hear a funny hum that sounds like human speech.

Sound is caused by something vibrating in the air. The ridges in the plastic strip make the strip vibrate when rubbed, making a humming sound. If the ridges have the proper depth and spacing, the humming noise can be made to mimic the sound of human speech.
whiz quiz
What was the first man-made invention to break the sound barrier?

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