Resonance Frequency Bridge Stability Science Fair Projects

Study how resonance frequencies can cause the collapse a bridge or to take down a building...

Sound

Most students think that sound is just something that we hear. However, the characteristics of sound can be manipulated and used. The characteristics of sound that can be manipulated include their frequency, their amplitude and their wavelength.

Objectives/Goals

Our goals in this project are firstly, to find the relationship between the resonant frequency of a wire compared to it's length and diameter; and secondly, to make a reasonable hypothesis, based on our finding and other research, of how we think the Tacoma Narrows bridge collapsed.

The Energy Lab allows you to experiment with energy conservation such as biomass, geothermal, hydorelectric, solar and wind. Ages 8 and up.

The Snap-Micro™ Controller Trainer is a way to learn about how micro-controllers are used. The easy to follow instructions guides you through the programming of basic commands by using flow charts to operate the micro-controller. Ages 12 and up.

Methods/Materials

We used the following items in our project: 6 steel wires of .025" in diameter, 4 steel wires of .05" in diameter, a block of wood, a 16" speaker, tone generator, glue, and an amplifier. This is the method we used: Glue the block of wood to the inside of the speaker. Cut the .025" wires so that there is 1 12", 1 11", 1 10", 1 9", 1 8" and 1 7". Cut the .05" wire so that there is 1 12", 1 11", 1 10" and 1 9". Insert the wires ½" into the wood. Attach the tone generator and the amplifier to the speaker. Turn on the tone generator and the amplifier and use the dial on the tone generator to experiment with the resonant frequencies.

Results

We expected a correlation between wire length, diameter, and resonant frequency. We graphed the results with wire length on the X axis and resonant frequency on the Y axis for both sizes of wire (.025" and .05"). We found that as the length of the music wire increased, the resonant frequency (Hz) decreased. We also found that one .025" wire that was 12" long had a lower resonant frequency than one .05" wire that was also 12" long.

Conclusions/Discussion

Our results achieved our goal in identifying the factors that affect the resonant frequency of different sized objects. After doing this project we are now able to better understand how the Tacoma Narrows bridge fell down and further improved our knowledge of the physics of mass in motion.