We utilize it to rapidly recognize the simple fact that there has been a rise in temperature (also known as the temperature approximation). Then, we use a standard thermometer that contains mercury. Has some pros: Easy to use, as well as quick. You are able to see that the temperature is rising. Having this drawback: He is obviously lying quite frequently. In addition, the same region of the skin might yield readings that vary by almost one degree when multiple readings are taken in succession on the same part of the skin.