Thermometrer work in clinic and hospital

Clinical thermometer

                   To measure the small variation in the temperature of the  human body clinical thermometers are used. It measures temperature in a very short range of 10°C from 35°C to 44°C. So it  accurately measures even small changes in body temperatures. 

           Clinical thermometer is similar in construction to a mercury  thermometer. It has a short, fine capillary tube with a constriction and a slight bend near the mercury bulb. The radius of the constriction is very small.

           When the thermometer is placed in the patient's mouth the mercury in the bulb gets heated and expands, it crosses the bend and goes up to a particular position. The temperature will be noted. When the thermometer is taken out of the mouth of the patient, the constriction prevents the mercury from flowing back into the bulb. then the thermometer is given a shake or a jerk, the mercury above the constriction comes down to the bulb.