Question

Why is a constriction provided in a clinical thermometer?

Answer 1

Clinical thermometer:

1. To measure human body temperature, doctors use a special thermometer, called clinical thermometer.
2. The scale in clinical thermometer is marked from ${94}^{0}F$ to ${108}^{0}F$.

There is a constriction near the bulb of the clinical thermometer:

1. This constriction prevents the mercury thread to flow back into the bulb so that the doctor can read the temperature accurately at his convenience.
2. To take the next reading the thermometer is given a jerk so that the mercury in tube fall back into the bulb.