Recommended for grades 9–12.
In this experiment, you will analyze various common sounds. You will use a Microphone connected to a computer. Logger Pro will display the waveform of each sound, and will perform a Fast Fourier Transform (or FFT) of the waveform. The FFT tells you the amplitudes and frequencies of a collection of sine waves that, when added together, would sound the same as the original waveform.
In the first part of the experiment, you will study the sound of a tuning fork which produces a tone composed mainly of a single frequency. Next, you will observe the production of overtones on a tuning fork. Overtones whose frequencies are multiples of the fundamental are called harmonic; other overtones are called inharmonic. You will also analyze the sound produced when you say two vowels. An FFT graph will reveal that your voice is composed of a large number of individual frequencies.
In the last part of the experiment, you will be given a problem to solve. How does the telephone company know what numbers you dial? Do those tones that you hear when you press the buttons on the telephone contain some kind of code? You can solve this problem and crack the code using the Microphone, the FFT analysis, and an inexpensive tone dialer.
- Use a Microphone to analyze the frequency components of a tuning fork and your voice.
- Record overtones produced with a tuning fork.
- Examine how a touch-tone phone works.
Sensors and Equipment
This experiment requires each of the following Vernier sensors and equipment (unless otherwise noted):
You may also need an interface and software for data collection. What do I need for data collection?
Download Experiment Preview
The student-version preview includes:
- Step-by-step instructions for computer-based data collection
- List of materials and equipment
Note: The experiment preview of the computer edition does not include essential teacher information, safety tips, or sample data. Instructions for Logger Pro and other software (such as LabQuest App or TI handheld software, where available) are on the CD that accompanies the book. We strongly recommend that you purchase the book before performing experiments.
See all standards correlations for Physics with Vernier »