How do dog whistles work? --- David, Pomonapark, Fla.
Marshall Brain Answers:
A dog whistle, if you want to think about it this way, is a musical instrument that produces a single note. The note is very high - so high that most humans cannot hear it. Yet dogs can hear it, because the hearing range of dogs is greater than the hearing range of most humans. See this page for a table showing the hearing ranges of many different animals. In that table, dogs have about twice the hearing range of humans.
As a general rule, the smaller the musical instrument, the higher the pitch it can create. So a Bassoon creates mostly low notes because it is big:
A piccolo creates notes with much higher pitches because it is small:
A dog whistle creates a note so high – typically 20,000 hertz - that many humans cannot hear the whistle at all. This video can help you to find out how high a note you can hear:
Most people cannot hear 20,000 hertz. Older humans often cannot hear above 15,000 hertz.
Dogs are generally able to hear notes much higher than humans can (up to 45,000 hertz), so most dogs hear a dog whistle's note without any problem. Then you can train the dog to do whatever you like when it hears the whistle. Here is a nice introduction: