Always been fascinated by the sounds of the crystal glasses. It turns out any cheap wine glass does the job. To do it with your kids is best to have a waterproof base and stick the glasses to the base with tape. Pour different quantities of water to the glasses as this results in different sounds even if all glasses are the same. Wet the fingers in the water and gently rub the edges to make the sounds.

If the kids are old enough start introducing notions like vibration, sound waves, frequencies and air pressure. Yeah, you can make science out of art and vice versa.