It’s well known that many animals are particularly sensitive to high-frequency sounds that humans can’t hear. Many commercial pest repellers based on this principle are available, most of them ...

"My son, Billy, picked up this silent dog whistle at a pet supply store." My friend George held out his hand to show me a small shiny metal whistle and then he continued, "Billy said that he was told ...

Dear reader, one of the skills I have always dreamed of nurturing is whistling. I am so envious of family and friends who can emit a sharp loud screech when they are trying to get attention. Sadly, my ...

In the summer of 1876, in a workshop on the outskirts of London, Francis Galton was busy fashioning brass tubing into an ultrasonic whistle. This unique sliding whistle would produce high-pitched ...