Question

Describe a clinical thermometer. How does it differ from the thermometer used in laboratory?

Answer 1

A clinical thermometer has a narrow stem and a long bulb filled with mercury (or alcohol). There is a small constriction in the stem above the bulb. When the bulb of the thermometer is held in the armpit or the mouth of a patient, the mercury (or alcohol) in the bulb rises in the stem.

When it is taken out of the patient’s body, the small constriction does not allow the mercury (or alcohol) from the stem to retreat into the bulb. Thus, this arrangement enables us to read the temperature of the patient’s body at ease after the removal of the thermometer from his body

The figure shows a clinical thermometer. It has a slight bend or kink in the stem just above the bulb, this kink is called the constriction which prevents the mercury from falling back all by itself. As the body temperature of a healthy person is 37°C, clinical thermometers are designed to measure temperatures between 35°C and 42°C.

Clinical thermometer