thumb|A medical mercury-in-glass maximum thermometer. 138px|thumb|An alcohol thermometer. thumb|right|180px|Thermometer with Fahrenheit (symbol °F) and Celsius (symbol °C) units.
thumb|A medical mercury-in-glass maximum thermometer. 138px|thumb|An alcohol thermometer. thumb|right|180px|Thermometer with Fahrenheit (symbol °F) and Celsius (symbol °C) ?units.