When calibrating a thermometer using the ice-water method, what is the correct target reading to set?

When calibrating a thermometer using the ice-water method, what is the correct target reading to set?

• A. 212°F (100°C)
• B. 32°F (0°C)
• C. 40°F (4°C)
• D. 100°C (212°F)

Answer: (B)

Calibrating with an ice-water bath relies on a fixed reference point: the freezing point of pure water at standard atmospheric pressure. In this setup, water and ice are in equilibrium, so the temperature stabilizes at 0°C (32°F). Set the thermometer to 0°C or 32°F so it reads true at that fixed point. If the device doesn’t read that value in the ice-water bath, adjust its calibration until it does. The other numbers correspond to the boiling point of water or a non-fixed value, which aren’t used as the calibration reference for this method.

Calibrating with an ice-water bath relies on a fixed reference point: the freezing point of pure water at standard atmospheric pressure. In this setup, water and ice are in equilibrium, so the temperature stabilizes at 0°C (32°F). Set the thermometer to 0°C or 32°F so it reads true at that fixed point. If the device doesn’t read that value in the ice-water bath, adjust its calibration until it does.

The other numbers correspond to the boiling point of water or a non-fixed value, which aren’t used as the calibration reference for this method.