How to Calibrate a Dial Thermometer

Most industrial and scientific thermometers can be calibrated to make them even more accurate. It is not difficult to calibrate a dial thermometer, but it is important that you do it correctly.

Difficulty: Moderately Easy

Instructions

1. First locate the calibration control for the thermometer. Usually this is either a thumbscrew or nut somewhere along the side or back of the thermometer. When you turn it either the needle or dial behind it should move slightly.

2. Next you need to prepare a situation where you have known temperature to which you can calibrate your dial thermometer. An ice water bath is the easiest and safest possible way to do this.

3. Take a medium-size container and fill it half of the way up with ice. Now pour cold water over the ice to fill the container the rest of the way. Wait 10-15 minutes for the temperature to stabilize. There should be still both water and ice in the container.

4. To calibrate a dial thermometer placed it in the ice bath and weight for the needle to settle on a temperature. If this temperature is 0°C / 32°F then the thermometer is correct. If it is not reading this temperature use the calibration control to correct it.

Tips & Warnings

• If you have another thermometer available you can test at various temperatures and doublecheck your calibration.