Experiment Study of Melde's string vibration

Topics covered:

- Visualize different natural modes of transverse vibration of a string.

- Visualize different natural modes of longitudinal vibration of a spring.

Principles and objectives:

The Melde's string is a string without stiffness, at the ends of which a sinusoidal exciter (Melde's vibrator) is attached on one side and an adjustable mass on the other side. The vibrator is controlled by an amplified function generator, or a function generator with an amplifier.

It is also possible to hang other masses on the one suspended at one end of the string, in order to vary its tension. The point of the string in contact with the pulley constitutes a node of vibration. An incident transverse wave will give rise to a reflected wave at this point.

When the other end of the string is sinusoidally excited, a resonance phenomenon occurs for certain specific frequencies. A natural mode of transverse oscillation of the string is then visualized; more or less numerous nodes are clearly visible (bellies and troughs).

For the observation of longitudinal waves, the string can be replaced by a vertically fixed spring. Adjusting the vibration frequency allows obtaining characteristic compression and rarefaction zones of a wave propagating along a spring.

- 1 Melde's vibrator (ref 222037) - 1 GBF 2 MHz (ref 295139) - 1 Amplifier for GBF (ref 239009) - 1 BNC banana cord (ref 283386) - 2 Modumontage support feet (ref 703453) - 1 Square rod 15 mm, length 70 cm (ref 703459) - 1 Clamping nut (ref 703452) - 1 Visible color cord 25 meters (ref 323018) - 1 Standing wave spring (ref 222002) - 1 Graduated meter (ref 744875) - 1 Elevator stand (ref 701967) - 1 Pulley on rod (ref 323017) - 1 Box of hooked masses (ref 703016) - 1 Dynamometer (ref 322027) - 1 Stroboscope (ref 322089)