Final answer:
To calibrate a thermometer accurately, it should be placed in ice water to ensure it reads 0°C (32°F), as this uses the reproducible freezing point of water as a reference. Boiling water at 100°C (212°F) can also be used, but it varies with altitude, making ice water more reliable for calibration.
Step-by-step explanation:
To ensure accurate temperature measurements, it's essential to calibrate a thermometer. The correct way to calibrate a thermometer is b) Place it in ice water and verify it reads 0°C (32°F). This method uses the freezing point of water as a reference, which is a well-established and easily reproducible standard condition. The process of calibration involves adjusting the thermometer to read the correct temperature when submerged in ice water because at standard atmospheric pressure, pure water freezes at 0°C (32°F).
It's important to note that while boiling water can also be used for calibration, it is not the method specified in the question. Boiling water calibration should ensure the thermometer reads 100°C (212°F) at standard atmospheric pressure, but because boiling points can vary with altitude, ice water provides a more consistent reference point for calibration.
Furthermore, temperature scales such as Fahrenheit, Celsius, and Kelvin, offer different units for measuring temperature. However, for calibration purposes, the Celsius and Fahrenheit scales are most practical because they are based on the physical properties of water.