1. Key ideas 1.3 Thermometer Thermometers Working principle
Liquid-in-glass
thermometer
Length of a liquid column increases with temperature
Resistance
thermometer
Resistance of a metal wire increases with temperature
Thermistor
thermometer
Resistance of a thermistor decreases with temperature

2. Two common types of liquid-in-glass thermometers:
Working principle
Rotary
thermometer
A bimetallic strip bends as temperature increases
Two different metal wires joined to form a close loop. The current flowing through the loop increases with the temperature difference between the junctions.
Thermocouple
thermometer
Two common types of liquid-in-glass thermometers:
mercury-in-glass thermometer
alcohol-in-glass thermometer

3. Clinical thermometers are used for measuring human body temperature.
Mercury
Alcohol
Range: –39 C to 357 C
Range: –115 C to 78 C
quick response
slow response
poisonous
non-poisonous
Clinical thermometers are used for measuring human body temperature.