Measurement in sport – the long and the short of it
Glossary
electronic quartz timing system. In these timing devices, an applied electric voltage causes a quartz crystal to vibrate (oscillate) at a remarkably constant rate. The oscillations of the crystal control the movement of the hands or the display of numbers. Quartz timing devices are very accurate and are almost unaffected by changes in temperature or position. (Quartz is crystalline silicon dioxide.)
International System of Units (abbreviated to SI). SI is based on the seven units shown in the table; all other units are derived from them. These units are represented by reproducible, agreed physical standards which allow accurate measurements to be made anywhere in the world. Australia's physical standards of measurement are maintained by the National Measurement Laboratory, which is a National Facility within CSIRO.
The seven SI base units of measurement
| Quantity | Base unit | Symbol |
| Mass Length Time Temperature Amount of substance Electric current Luminous intensity |
kilogram metre second kelvin mole ampere candela |
kg m s K mol A cd |
newton. The SI unit of force. One newton gives an acceleration of 1 metre per second per second to a mass of 1 kilogram. The weight you feel when you hold an average size apple in your hand is about one newton (mass is about 0.1 kilogram and gravitational acceleration of about 10 metres per second per second). It is named after Sir Isaac Newton.
transducer. A device that converts one form of energy into another. For example, an electric jug converts electrical energy into heat energy. A transducer connected to a starter's pistol converts sound energy into electrical energy.
Page updated August 2006.