Measure the frequency of a plucked string

This project must be done by individuals or teams of 2.

We have examined in class the normal modes of oscillation of a string stretched between two fixed posts, placed under tension. There are lots and lots of formulae which predict the frequencies with which such strings ought to oscillate; they depend upon the tension and the linear mass density of the string, and on the length of the string.

Your job is to set up a real string, stretched under some known tension, and verify that these predictions are correct. If they aren't, you must explain the discrepancies.

Here are some tips:

Hanging a known mass from one end of the string is a good way to set the tension.
One way to measure the frequency of a string is to listen to it carefully, and compare it to the frequency of some known instrument: tuning forks, a piano, a guitar, etc.
Another way to measure frequency is to record a sound, digitize it, and then analyze the wave form with software.
Another way to measure the frequency is to illuminate the string as it is vibrating with a strobe light. There are a number of applications for smartphones which claim to produce bursts of light at set frequencies; if those don't work, you might ask the instructor for a real strobe light.

Hand in sheets of paper, showing all your work.