| Bibliographic Entry | Result (w/surrounding text) |
Standardized Result |
|---|---|---|
| Sebastian Haskel and David Sygoda. Biology, A contemporary Approach. New York: Amsco, 1996. | "The human ear has receptors that can detect sound frequencies raging from 16 vibrations to20,000 vibrations per second." | 16–20,000 Hz |
| Lerder, Francis C. "The Human Ear." Encarta Encyclopedia Deluxe 2004. CD-ROM. | "The maximum range of human hearing includes sound frequencies from 15 to about 18,000 waves,or cycles, per second." | 15–18,000 Hz |
| Peter Hamlin, St. Olaf College. Basic Acoustics for Electronic Musicians. January 1999. | "The human ear can hear frequencies ranging from about 20 cps. to about 20,000 cps (although an individual might have a considerably smaller range)." | 20–20,000 Hz |
| Harris, Wayne. Sound and Silence. Termpro. Originally appeared in the March/April 1989 issue of Car Stereo Review magazine. | "The normal range of hearing for a healthy young person is 20 to 20,000 Hz; hearing deteriorates with age and with exposure to unsafe volume levels." | 20–20,000 Hz |
What is sound and frequency? Sound is a longitudinal mechanical wave of any frequency. Frequency is the number of cycles, or complete vibration experienced at each point per unit. Frequency is measured in hertz. The hertz, Hz, is the derived SI unit of frequency. The frequency of a sound wave determines its tone and pitch. The frequency range of a young person is about 20 to 20,000 hertz.
The human ear is capable of hearing many of the sounds produced in nature, but certainly not all. Some low frequencies like a heart beat of 1 or 2 Hz can not be heard, just like sonar sounds produced by dolphins which are too high. Any frequency that is below the human range is known as infrasound. It is so low that it may be detected by a creature with big ears, such as an Elephant. In fact, recent research indicates that elephants also communicate with infrasound. Ultrasound, on the other hand, is above the range of the human ear. Bats, whales, porpoises, and dolphins use ultrasound for navigation. Most bats can detect frequencies as high as 100,000 Hz!
Rizwan Choudhary -- 2004