Did you know that Benjamin Franklin invented the glass harmonica? It consisted of glass hemispheres attached to a turning rod and he played it by running a wet finger across the rims of the glasses. The glasses were of different sizes, so each produced different vibrations resulting in different sounds.
Try making your own version:
- Line up glasses of different sizes on a firm surface
- Pour water into each glass
- Have water in glasses makes it easy to keep your finger wet
- Run your forefinger quickly around rims. (notice ther sound varies with the thickness of glass)
