The hertz (symbol: Hz) is a unit of time which measures frequency. Frequency is how often something happens. A frequency of 1 hertz means that something happens once a second. The note Middle C (the C in the middle of the piano) is 262 Hz. This means there are 262 vibrations every second, which is heard as the note Middle C, when that piano key is played. Humans are able to hear sounds between 20-20 000 Hz. Owls are able to hear sounds 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