The most accurate thermometer is the:

• A. Glass stem thermometer.
• B. Electronic thermometer.
• C. Dial-type thermometer.
• D. Pocket dial-type thermometer.

Answer: (A)

Accuracy in a thermometer comes from how directly and stably the sensing element translates temperature into a reading. Glass stem thermometers use mercury (or alcohol) in a fine capillary, which expands in a highly predictable, linear way and reads on a precise scale. That combination gives highly reproducible, exact measurements when used correctly, making them the most accurate option among the types listed.

Dial-type and pocket dial-type thermometers rely on mechanical parts like bimetallic coils, which can drift, stick, or read with coarser precision, reducing accuracy. Electronic thermometers are fast and generally accurate, but readings can be affected by battery level, sensor placement, and calibration issues. So, the glass stem thermometer yields the most precise reading in typical clinical use.