Sound propagation: glass pairs
Why does a second glass connected to the first glass with a wire vibrate when we hit the first glass?
It must be remembered that the vibrations of the second glass only occur if the glasses have the same pitch level when they are struck or rubbed (use water to adjust levels if necessary)!
Close observation will show that even the water in the second glass starts to vibrate.
Information and ideas:
Setting up the experiment: Two glasses are put at a small distance from each other. A knitting needle or something similar is laid over the two glasses.
Using a moist finger, rub the first glass gently along its rim. A sound is produced, and after a short time the needle begins to vibrate on the second glass as well.
Relevant for teaching:
Vibrations and waves