Ten Things You Should Do with a Tuning Fork
Once the tuning fork is vibrating, it will “sing” in several unwanted frequencies. Touching near the base reduces these, leaving the intended tone oscillating. It should be inaudible at an arm's length.
Using a speaker cone as a simple microphone. This general arrangement is for investigating the frequency and intensity of a tuning fork.
Where to expect the nodal planes. The plane between the tines is the loudest. Listen for these while holding a vibrating tuning fork near an ear and rotating it.
Only the mounted fork on the right is struck. Both boxes have an opening where they are brought together. The fork on the left is sent into vibration because it shares the resonant frequency. This induced vibration is better demonstrated when a hanging ball is knocked outward.
When a tuning fork is struck very hard, multiple vibrational modes are audible. With the help of an oscilloscope, this superposition is visually demonstrated.
It is easy to clip a solar cell to a set of speakers. Obstructing the laser dot with a vibrating tuning fork can send its signal across the room and amplify the vibration for all to hear.
A sine curve generated by reflection from a single vibrating 128-Hz tuning fork. This image was produced by rotating the fork while a laser was being reflected to a wall about three meters away.
Arrangements that will produce Lissajous figures. Note that the tuning forks should be close to one another and that increasing the distance to the wall will improve the visibility by amplifying the trace.
Fish-shaped Lissajous figure made by reflecting a diode laser from tiny mirrors hot-glued on the G 384-Hz and the C 256-Hz tuning forks, thus providing the signature trace of a 3:2 ratio. 11
The three materials that allow one to immediately measure the speed of sound. Note that the height of the tube is 25 cm.
These two identical tuning forks will no longer have identical frequencies.
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