One effective way to calibrate a thermometer is the ice-point method, which involves these steps:
- Fill a container with crushed ice and add clean cold water to create an ice-water slurry.
- Stir the mixture and insert the thermometer probe into the ice water, ensuring it does not touch the container's sides or bottom.
- Hold the thermometer in place for about 30 seconds or until the reading stabilizes.
- The thermometer should read 32°F (0°C). If it does not, adjust the thermometer accordingly—dial thermometers can be adjusted by turning a nut below the dial, while digital thermometers may have a reset or calibration button.
- After adjustment, recheck the reading to confirm accuracy.
This method is widely used because it provides a reliable fixed point for calibration and is suitable for most dial and digital thermometers
. Alternatively, the boiling-point method can also be used, where the thermometer is placed in boiling water (212°F or 100°C) and adjusted if the reading differs, but the ice-point method is more common and safer for regular calibration
