Final answer:
To calibrate a thermometer using the ice-point method, the temperature should be set to 0°C, which is the freezing point of water on the Celsius scale.
Step-by-step explanation:
When using the ice-point method to calibrate a thermometer, the temperature reading should be set to 0°C. This is because, on the Celsius scale, the freezing point of water is defined as 0 degrees Celsius.
This calibration point is based on the physical property that pure water at sea level freezes at this temperature.
By ensuring the thermometer reads 0°C when placed in an ice-water mixture, you can confirm that it is properly calibrated for further measurements within the range of the Celsius scale, which sets the freezing point and boiling point of water at 0°C and 100°C respectively.