Let the students tune a guitar in different ways. Let them find information on internet about the different tuning methods. Perhaps the students know other ways as well.
The ways to tune the guitar are:
- Using of beats
One way is to play the same tone on different strings (by shortening one of the strings). Play these tones together, when the two strings are slightly out of tune, beats will occur. When the strings are well tuned, there will be no beat.
See (and hear) for an example of beats on the double bass: http://youtu.be/a0VWWbr6O1I In this movie you see the double bass (starting out of tune) and you can hear the sound of it. This sound is recorded with Coach and you see the beats occurring in the pattern (Around t=32 s in the movie) When the tuning of the strings is changed, you see less beats in the same time (t = 56 s): the strings are more in tune then before. At the end of the movie there are almost no beats ( t = 1 m 30 s ). Take notice that the graphs showed in this movie are all given for a measure time of three seconds.
- Using harmonics
By playing harmonics on different strings, the same tone should occur. Let the students find out which frets are used for this.
- Using resonance
When a string that produces a low tone, is shortened, there is a position where this string produces the same tone as the string next to this. Find this position and play the shortened string. When both strings are well tuned, the not-shortened string will resonate.
See for an example of resonance with strings the next movie of a double bass: http://youtu.be/d8uH7SeAtZA.