by Allie Ashlock, 10
Mr. McCorkendale’s Chemistry 2 class did an advanced version of the lab the Biology 1 class will be doing next week. For this lab, they are building phones using cups and strings and they will try to determine which of several variables will produce the loudest phone.
When we talk, our vocal cords make molecules in the air vibrate. (You can feel the vibrations by holding your hand against your throat while you talk.) Those vibrating air molecules make other air molecules around them vibrate, and so on, which is how sound travels through the air. (Different pitches of sound move in waves that have different spacing between them—or “frequency.”) Other sources of sound, such as guitar, violin or piano strings are good examples of how vibrations can generate sound.
Inside our ears are tiny sensitive hairs. They pick up the vibrations and transmit that information to our brains, which interpret it as sound. The brain interprets sounds as having different pitches, or tones, based on the frequency, or spacing, of the waves.
But the particles in air are spread out from one another more than particles in a liquid or solid. So sound vibrations tend to peter out before they travel very far. Having a soft connective material, such as cotton string—which has a higher density, or number of molecules in a given amount of space, than air—can help the sound waves move over a greater distance.
For this experiment, each person in the class is testing a different variable and they will use their results to propose a follow-up experiment to get a better answer. Stay tuned – we’ll bring you updates and a final result!
Photos by Emily Bybee, 10