I’m guessing you’ve seen the emergence of the cicadas and have probably heard them as well. This year is a unique year as we haven’t seen these 13-year and 17-year broods come out at the same time for the past 221 years, or since 1803. As we’ve seen the past few months in ChemShorts, sound is made by vibrations.
Materials:
• Popsicle sticks
• Paper
• Pencil
• Scissors
• Toothpicks - round
• Rubber bands
Experiment:
Trace on the paper the shape of the popsicle stick and cut it out using the scissors. Put the paper between two popsicle sticks and tightly wrap a rubber band around the end. Perpendicular to the stick, slide the toothpick between the sticks as close to the rubber band as possible. Put another toothpick between the sticks on the other end and tightly wrap the other end of the sticks together with another rubber band. If you blow between the sticks (hard? soft?) you will cause the paper to vibrate giving a sound similar to a cicada.
What’s happening?
This is the song of the male when trying to find a partner. However, they use their muscles to vibrate the tymbals (rubbery substance seen in the picture above) on their bodies while the female cicada makes a clicking sound – like when you snap your fingers – by using her wings.
Extension:
Use different size sticks or different thicknesses of paper. Make the toothpick spacer larger or smaller. A quick and easy way to do this is to put a blade of grass between your thumbs and blow between them to make a grass whistle.
References:
https://www.youtube.com/watch?v=-CdMEcSRivg
https://askabiologist.asu.edu/cicada-sound
https://www.artofmanliness.com/living/games-tricks/cool-uncle-tricks-how-to-make-a-grass-whistle/
To view past “ChemShorts for Kids” activities, go to:
https://chicagoacs.org/ChemShorts.
