How is temperature measured?
Temperature is measured using a thermometer. Many types of thermometers are present including analog and digital ones. Analog thermometers use mercury inside a glass tube since it expands under heat. Mercury thermometers have to be handled with care since mercury is poisonous on ingestion or inhalation.
Thermometers can measure temperature from different body sites including:
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- Mouth: The mouth is the most used site for temperature measurement. The thermometer is placed under the tongue, and the patient is asked to keep it for a few minutes. This method is not suitable for children or non-cooperative individuals since they can bite the thermometer bulb and ingest the mercury.
- Rectum: This is the most accurate measuring site for temperature. Children are usually the ones that need rectal temperature measurement, since their core temperature can differ from their skin surface temperature and measuring by mouth is not suitable for them.
- Ear: The ear is also a common site for quick temperature measurements using digital thermometers.
- The armpit: The armpit is the least accurate site for temperature measurement since it can easily be cooled without affecting the body’s real temperature.
Different values exist for different reading sites. In general, you can add half a degree to the recorded armpit temperature to get the correct reading.