Thermometer
A device for measuring temperature.
A thermometer must be placed in good thermal contact with the system being studied.
Temperatures are determined by measuring a property whose variation with the temperature is known. This property can be a length, e.g. thermometers with liquid columns, a volume or a pressure, e.g. gas thermometers, a voltage, e.g. thermocouples, and an electrical resistance, e.g. thermistors.
Beckman thermometer
This is a highly accurate mercury thermometer which is used in quantitative but not absolute temperature measurements.
It is not used for routine temperature monitoring of the contents of a flask or beaker.
