"A sensor that uses sound waves to measure temperature could replace thermometers that lose accuracy in harsh environments such as nuclear power stations. Scientists at UK measurement institute the National Physical Laboratory (NPL) are using the long-established principle that sound travels faster through warm air to create a cheap and robust thermometer that doesn’t need recalibrating or replacing. They hope the device would be used to measure extremely high temperatures or in locations where it would be difficult to change the thermometer, such as in nuclear reactors."