<Dl> <Dt> Thermochromism </Dt> <Dd> Some compounds exhibit thermochromism at distinct temperature changes . Thus by tuning the phase transition temperatures for a series of substances the temperature can be quantified in discrete increments, a form of digitization . This is the basis for a liquid crystal thermometer . </Dd> </Dl> <Dd> Some compounds exhibit thermochromism at distinct temperature changes . Thus by tuning the phase transition temperatures for a series of substances the temperature can be quantified in discrete increments, a form of digitization . This is the basis for a liquid crystal thermometer . </Dd> <Dl> <Dt> Blackbody radiation </Dt> <Dd> All objects above absolute zero emit blackbody radiation for which the spectra is directly proportional to the temperature . This property is the basis for a pyrometer or infrared thermometer and thermography . It has the advantage of remote temperature sensing; it does not require contact or even close proximity unlike most thermometers . At higher temperatures, blackbody radiation becomes visible and is described by the colour temperature . For example a glowing heating element or an approximation of a star's surface temperature . </Dd> </Dl> <Dd> All objects above absolute zero emit blackbody radiation for which the spectra is directly proportional to the temperature . This property is the basis for a pyrometer or infrared thermometer and thermography . It has the advantage of remote temperature sensing; it does not require contact or even close proximity unlike most thermometers . At higher temperatures, blackbody radiation becomes visible and is described by the colour temperature . For example a glowing heating element or an approximation of a star's surface temperature . </Dd>

Name the instrument which is made on the basis of expansion of heat