Wb-6 The Monochord (The Sonometer)
Published: Tuesday 14 March 2006 - Updated: Wednesday 30 March 2011
To demonstrate the fundamental law of vibration of a stretched string.
- The monochord
- Set of attached weights
- Frequency meter if required
Click on pictures to enlarge.
The monochord consists of a sounding box which supports a wire whose length of vibration may be adjusted by the movable bridge B. The tension is adjustable by the weights D. The equation for the vibration of a stretched string may be verified .
The equation above shows that:
for a string under constant tension the frequency varies inversely as the length;for a string of constant length the frequency is proportional to the square root of the tension;for a given length and constant tension the frequency varies inversely as the square root of the mass/unit length.
which are Mersenne's laws.