Science Project for Using a Cone to Amplify Sound
When you speak, sound waves come out of your mouth and travel in all directions. This means that only some of the waves go in the direction you want them to -- toward the person you're talking to, for example. If you talk into the narrow end of a cone, the sides of the cone trap the sound waves and stop them from dispersing outwards. All the sound is forced to travel through the open end of the cone, which makes the sound seem louder. Try using cones of different materials to determine which material amplifies sound the best.
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Things You'll Need
- Digital or tape recorder
- Decibel meter
- Construction paper
- Tape
- Printer paper
- Aluminum foil
- Poster board
- Tissue paper (gift wrap type)
- Stiff fabric
Instructions
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Record your voice on a tape recorder or digital recorder to make sure that the sound begins at the same volume for each trial. Set the recorder on a table, and set a decibel meter on another surface at least 6 feet away.
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Face the recorder toward the decibel meter. Play the recording. Write down how many decibels the meter registers.
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Roll a sheet of heavy construction paper lengthwise into a tube. Widen one end while holding the other end nearly closed, creating a cone. Tape the paper in place, to secure the cone shape.
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Hold the narrow end of the cone up to the speakers on the recorder, and turn the wide end of the cone toward the decibel meter. Play the recording, and write down the decibel reading.
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Repeat the process with cones made of different materials. Try a sheet of lightweight printer paper, aluminum foil, poster board, tissue paper and a stiff fabric that can hold the cone shape -- or any materials you prefer. Use the same size sheet of each material, and make each cone's dimensions -- the size of the openings at each end -- exactly the same.
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Compare the decibel readings of the materials tested. Determine which materials amplified sound the best, and create a chart to illustrate the different readings. Draw a conclusion based on your findings.
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Tips & Warnings
For a variation of this experiment, try using cones of different sizes instead of different materials. Start with larger and smaller sheets, so your cones are different lengths, or widen the open end on some cones and keep it narrow on others.
Perform all your tests in a row, without stopping. Changes in weather can affect how sound travels, so your results will be more reliable if you do all your tests at the same time.
References
Resources
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