Why is the thermometer kept under the tongue?

Measuring body temperature accurately is crucial in diagnosing and managing illness. A thermometer is an instrument used to measure the degree of hotness or coldness of an object. It has wide applications in medicine, meteorology, industry, technology, and scientific research.

The normal body temperature of an adult is about 98.6°F (37°C). A temperature of 100.4°F (38.8°C) or higher indicates fever.

Methods of Measurement

1. Oral method – Placed under the tongue; most common, as blood flow here reflects internal body heat.
2. Rectal method – Inserted gently into the rectum; gives accurate core temperature.
3. Axillary method – Placed in the armpit; often used for infants or patients where oral measurement isn’t suitable.

Key Parts of a Thermometer

• Temperature sensor – Detects changes in temperature.
• Scale/Display – Converts the detected change into a numerical value for reading.