Explain how two sets of identical but oppositely travelling waves are established in the microwave and air column experiments described in Practical Activity 14.1.

PRACTICAL ACTIVITY 14.1

Observing stationary waves

Here we look at experimental arrangements for observing stationary waves, for mechanical waves on strings, microwaves and sound waves in air columns.

Stretched strings: Melde’s experiment

A string is attached at one end to a vibration generator, driven by a signal generator (Figure 14.6). The other end hangs over a pulley and weights maintain the tension in the string. When the signal generator is switched on, the string vibrates with small amplitude. Larger amplitude stationary waves can be produced by adjusting the frequency.

Figure 14.6: Melde’s experiment for investigating stationary waves on a string.

Transcribed Image Text:

vibration pulley string generator weights signal generator