Two tuning forks with slightly different frequencies give beats.
The addition of a small lump of Blu-Tack to a tuning fork changes its frequency. When struck along with a matching fork that has no Blu-Tack, beats result.
NCEA & Science Curriculum
PHYS 3.3, PHYS 3.4
The forks in the photo above nominally produce 256 Hz. The addition of the Blu-Tack results in beats at a few Hz. You can adjust the increase the beat frequency by adding a larger lump of Blu-Tack. The forks have to be held near the head.
Individual teachers are responsible for safety in their own classes. Even familiar demonstrations should be practised and safety-checked by individual teachers before they are used in a classroom.
Beats from speakers || Combining Sounds
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Related to PIRA 3B60.10
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