You will need:
- Crystal wineglass (or any other crystal glass)
- Water
Create some musical notes using a wineglass.
INSTRUCTIONS
- Pour 2 cm of water into the wineglass. Make sure your hand is not oily or greasy even a little bit.
- Gently dip a finger in water and slide it along the rim of the wineglass.
- Keep sliding it until your glass begins to ring. Once it is ringing clearly, stop and wait for it to die down.
- Start sliding your finger over the glass once again and let it ring loud. As it continues to ring, try pouring the water out of the glass.
- The ringing will probably die down. Tip the glass back till it is straight.
- Try getting the water till the brim by tipping it and then straightening it again while it is ringing.
- Does the shift in water affect the ringing?
RESULT
By sliding your finger over the rim, your finger creates vibrations by slipping and sticking to the glass, which deform the glass in an oval shape, in the top to bottom and right to left direction. Gradually, these vibrations build up and vibrate in the air creating sound. This effect is called resonance, and its frequency is known as resonant frequency. Different glasses produce different frequencies. By getting the water near the rim, the rim starts to get heavier and the ringing dies down. But when we tip the glass back straight, the water is once again moving away from the rim returning it to its normal weight and the ringing begins to increase.
