Maximum Thermometer
A special kind of mercury-in-glass thermometer, called a maximum thermometer, works by having a constriction in the neck close to the bulb. As the temperature rises the mercury is pushed up through the constriction by the force of expansion. When the temperature falls the column of mercury breaks at the constriction and cannot return to the bulb thus remaining stationary in the tube. The observer can then read the maximum temperature over the set period of time. To reset the thermometer it must be swung sharply. This design is used in the traditional type of medical thermometer.
Read more about this topic: Mercury-in-glass Thermometer
Famous quotes containing the word maximum:
“Probably the only place where a man can feel really secure is in a maximum security prison, except for the imminent threat of release.”
—Germaine Greer (b. 1939)