What mixture of water is commonly used to calibrate a thermometer?

The mixture commonly used to calibrate a thermometer is a 50/50 combination of ice and water. This mixture creates a reliable reference point at 0 degrees Celsius (32 degrees Fahrenheit), which is the freezing point of water. When you immerse the thermometer in this mixture, it should read 0°C, allowing you to ensure that the thermometer is accurately calibrated.

A mixture of 70/30 or 30/70 would not provide a reliable reference temperature for calibration purposes, as they do not align with the freezing point of water. A 100/0 mixture indicates pure water without any ice, which does not serve as a calibrating standard since it does not represent a freezing point scenario. Therefore, the 50/50 mixture is optimal for effective thermometer calibration, as it establishes a standard temperature that can be consistently replicated.