Speaking of hearing and sound, humans have an audible range of 20 Hz to 20,000 Hz. A Hz is a Hertz or one cycle per second. Any vibration with frequencies outside of that range cannot be heard by humans, but they can be heard by dogs. Dogs have an audible range as high as 50,000. Just to put this into perspective, when we age our human audible range drops to a high of only 10,000 Hz. Those frequencies above 20,000 are called ultrasonic, so dogs have ultrasonic hearing. Don’t confuse the term ultrasonic with supersonic. Supersonic is moving faster than the speed of sound, which by the way is about 340 m/s in air. I thought I would throw in a little science just to make your day great.