The hertz (symbol: Hz) is a unit time to measure frequency. It tells how often something happens. A frequency of 1 hertz means that something happens once a second. The pitch of the note Middle C (the C in the middle of the piano) is 262 Hz. This means there are 262 vibrations every second when a Middle C is played. Humans' ability to hear sounds is between 20-20 000 Hz. Owls' ability to hear sounds is between 200-12000 Hz.
The unit is named after Heinrich Rudolf Hertz.
Bigger units[change | change source]
1000 hertz is 1 kilohertz. 1000 kilohertz is 1 megahertz, 1000 megahertz is 1 gigahertz and so on.
Examples[change | change source]
- The frequency of the Earth's spinning (once per ~24 hours) is about 12 microhertz (much smaller than 1 Hz).
- The hertz is sometimes used to measure the power of a processor in computing and electronics.
- Amateur radio in the United States Of America is at different frequencies between 1.8 to 1300MHz
- Air traffic control uses frequencies between 3 and 25MHz as well as frequencies between 108 and 136MHz