The two main differences between a clinical and an ordinary thermometer are their functions, because an ordinary thermometer measures humidity, while a clinical thermometer measures the temperature of the human body, according to Dictionary.com. However, a clinical thermometer cannot read temperatures below 34 C or over 44 C.
A clinical thermometer is calibrated so that it can measure the temperature of a human. Most of these thermometers have liquid inside of them, such as mercury or colored liquids, that react to temperature change. This thermometer is placed under a person's tongue or in the underarm region of the body, while others are placed in the rectum or ear canal. A clinical thermometer can provide different readouts because it uses either a Fahrenheit scale, a Celsius scale or the Kelvin scale. An ordinary thermometer is commonly referred to as a dry-bulb thermometer. Most people use this thermometer to measure other types of temperature, such as humidity levels or the outside temperature. This thermometer can show higher temperatures because it is built to withstand different temperature ranges. However, to obtain the right humidity levels, the dry-bulb thermometer is paired with a wet-bulb thermometer. This allows an individual to record a relative number for the humidity levels.