Calibrating a thermometer scale

Steps:

• Recognize the glass tube with two marks as a thermometer's capillary tube.
• Identify the marks as fixed points: ice point (0°C) and steam point (100°C).
• Divide the length between these points into 100 equal parts to create the Celsius scale.
• This process standardizes temperature measurement.

Why B is correct:

• Thermometer calibration defines the Celsius scale by dividing the distance between 0°C (ice-water mixture) and 100°C (steam at 1 atm) into 100 equal degrees, as per the original definition by Anders Celsius.

Why the others are wrong:

• A: Spring extension uses Hooke's law (F = kx) to find weight from displacement, not tube division.
• C: Manometer measures pressure via liquid column height difference, without fixed 100-part division.
• D: Measuring cylinder has pre-marked volume graduations, not user-divided length into 100 parts.

Final answer: B