Can You Hear Me Now?
2011 VIRTUAL SCIENCE FAIR ENTRY
Objective: This project was to determine if heat affects the frequency of sound waves. It is expected that less sound would be collected at a lower temperature than a higher one. Sound travels faster under water than on land, because more pressure is present. The more heat in the air, the higher air pressure so in high pressure sound travels faster. More sound would be collected in 15 seconds at the temperature of 450°F.
Materials and Methods: One parabolic sound collecting dish was used with a microphone in the center connected to an IPod Touch with the freqCounter app on. The thermostat was then set on 70°F. The dish was placed 197 cm away from the oven. Then a long “middle C” was played using a tuner metronome at 0, 225, 325, 425, and 450°F.
Results: The higher temperatures were constantly better than the lower ones. The last variation was a little bit smaller than the second to last one though. Overall there was a big difference between the fist and the last variation.
Conclusions: Higher temperatures do affect how fast the frequency is. The higher the temperature, the more sound is collected.
- Physical Science
- 7th-9th grade
Difficulty of the Project
- $80 (excluding the IPod, tuner metronome and the oven)
- Gloves should be worn while cutting wood and handling the hot oven.
Time Taken to Complete the Project
- 40 hours
The project is about how heat and distance affect frequency collected. The goal of this experiment is to see how heat and distance affect the amount of sound collected.
Materials and Equipment
For Dish and Frame
- Iron wok or similar bowl, about 15 ¾ inches in diameter-1
- 4 inch diameter circular fixture box for hanging lamp with 1-inch diameter center hole-1
- Threaded rod-46 cm
- Headset with microphone that is compatible with the IPod Touch-1
- IPod Touch-1
- IPod App- FreqCounter-1
- 3 ½ x 3 ½ x 25cm piece of pine wood-2
- 30 Diameter cm circular piece of ply wood-1
- 3 ½ x 3 ½ x 47cm piece of pine wood-1
- 4 inch atrium grate-1
- ⅜ inch stove bolts and nuts for cabinet hinges-2
- Nuts ¼ inch square and 2 wing nuts ¼ inch-3 each
- Large fender washers 1 ½-inch -4
- 1-inch nails-8
- Corner braces, each with four screw holes-2
- Short wood screws-9
- Stove bolts for pivot seal 2 by 5/16 inches and nuts to fit-2 each
- ¼ inch t-sleave-2
- Power drill with ¼ and 10/32 bits-1
- Grinding wheel attachment for drill-1
- Hacksaw for fine-tooth material-1
- Tuner Metronome-1
The materials were mostly purchased from a hardware store, excluding the tuner metronome, which was purchased at a music store. The materials were readily available.
Sound is a very big part of nature. It is created by objects vibrating, which in turn makes air or another substance in the air to create sound waves, which can be heard. Louder sounds are made from larger vibrations, while softer sounds are created from smaller vibrations. The SI unit to measure frequency is hertz (Hz). Frequency is how many times a wavelength vibrates per second. The average human can hear between 20 and 16,000 Hz. Barometric pressure also affects the frequency of an object. The more barometric pressure present, the higher the frequency.
A parabolic sound collecting dish is a good way to measure the frequency of sound. A parabolic sound collecting dish can be used to listen to distant sound and noises, and measure its frequency. Once the dish is placed in the desired position, the sound will travel through the air and bounce off the dish into the microphone, where the frequency can by recorded. The unwanted sounds bounce off at different angles, so they never reach the microphone.