Question

Write the construction of a clinical thermometer.

Answer 1

Hint: The clinical thermometer is also known as Fahrenheit scale thermometer. It is extensively used to measure the body temperature of human beings when feeling sick or abnormal. This is the reason it is called a clinical thermometer. This thermometer is also referred to as a doctor's thermometer.

Complete step-by-step answer:
A clinical thermometer usually consists of cylindrical bulb b which usually contains mercury in it. A capillary tuber t of uniform and fine bore is attached to the bulb. Just above the bulb of the thermometer, at point c, the bulb is made to be narrow and bent. As we know, our human body temperature varies from ${95}^{0}F$to ${110}^{0}F$, the thermometer is calibrated in this temperature range. In this thermometer, each degree is divided into five small equal divisions. Besides, the temperature of a healthy man will be around ${98.4}^{0}F$, so a bold mark is made on the surface of the thermometer at this thermometer. We say the temperature of the body is abnormal when the mercury is above the mark or below mark extremely.
In this way, the clinical thermometer is constructed.

Additional Information: We usually shake the thermometer thoroughly before checking the thermometer so that the mercury remains at low level and inside the bulb. After this, it is placed under the tongue or arms which results in an increase in the mercury level gradually. Some amount of mercury flows from b to c. When taken out, the mercury level contracts. The level of mercury above c indicates the temperature of the body. After noting the temperature, the thermometer must be shaken again so that mercury goes back to the bulb.

Note: The reason why we choose mercury instead of water is because water has high tension and it sticks to the glass of the thermometer easily. Also, mercury boiling and melting points are abnormal and mercury can’t be evaporated because of our body’s temperature. Also, water gets evaporated easily due to the weather conditions. Therefore, mercury is highly recommended for thermometers.