Sparkling sounds

We’ll soon be wielding handheld ultrasonic cleaning tools to help with the
household chores, according to soap conglomerate Procter & Gamble. About the
size of a large electric toothbrush, their gadget has a chisel-shaped ultrasonic
cleaning head, and a choice of two surfaces. The hard head would be suitable for
soft fabrics such as clothing, while the soft one would be used for the kitchen
or bathroom. Rechargeable batteries vibrate the head vigorously at 50 kilohertz,
say P&G in WO 01/36115/6. The energetic vibrations would break adhesive
bonds, allowing stains to be lifted onto a cleaning wipe. P&G say bathtub
stains…