How do temperature changes affect a tuning fork's frequency?
The hypothesis that the frequency of sound from a tuning fork will decrease when the temperature increases is proven to be true. As the temperature of the tuning fork increases, the atoms inside the fork will gain kinetic energy and vibrate more. This will cause the fork to expand and become longer. As can be seen from the formula given in the overview section, the frequency of the tuning fork is inversely proportional to the square of the tuning fork length. Therefore any slight increase in the tuning fork length will cause a reduction in the sound frequency produced.
Tuning forks are not only used to calibrate musical instruments anymore. They are also used by doctors to evaluate patients hearing, calibrating speed detection radar and in temperature measurement devices.
What would happen if the experiment was repeated by using a tuning fork made from a different material?
The experiment can be repeated using tuning forks of different frequencies.
Tuning Fork - http://en.wikipedia.org/wiki/Tuning_fork
Longitudinal waves and tuning forks - http://www.physicsclassroom.com/mmedia/waves/tfl.cfm