How Will You Calibrate a thermometer in degree Celsius.. ..?

Answer 1

The thermometer was used by the originators of the Fahrenheit and Celsius scales.

Anders Celsius, a Swedish Astronomer, devised the Celsius scale, which was described in his publication the origin of the Celsius temperature scale in 1742.

Celsius used two fixed points in his scale: the temperature of melting ice and the temperature of boiling water. This wasn't a new idea, sinceIsaac Newton was already working on something similar. The distinction of Celsius was to use the melting temperature and not the freezing temperature. The experiments for reaching a good calibration of his thermometer lasted for 2 winters. By performing the same experiment over and over again, he discovered that ice always melted at the same calibration mark on the thermometer. He found a similar fixed point in the calibration of boiling water vapour (when this is done to high precision, a variation will be seen with atmospheric pressure). At the moment that he removed the thermometer from the vapour, the Mercury level climbed slightly. This was related to the rapid cooling (and contraction) of the glass.

The air pressure influences the boiling point of water. Celsius claimed that the level of the mercury in boiling water is proportional to the height of the barometer.

When Celsius decided to use his own temperature scale, he originally defined his scale "upside-down", i.e. he chose to set the boiling point of pure water at 0 °C (212 °F) and the freezing point at 100 °C (32 °F).[1] One year later Frenchman Jean Pierre Cristin proposed to invert the scale with the freezing point at 0 °C (32 °F) and the boiling point at 100 °C (212 °F). He named it Centigrade.[2]

Finally, Celsius proposed a method of calibrating a thermometer:

1. Place the cylinder of the thermometer in melting pure water and mark the point where the fluid in the thermometer stabilises. This point is the freeze/thaw point of water.
2. In the same manner mark the point where the fluid stabilises when the thermometer is placed in boiling water vapour.
3. Divide the length between the two marks into 100 equal pieces.

These points are adequate for approximate calibration but both vary with atmospheric pressure. Nowadays, the triple point of water is used instead (the triple point occurs at 273.16 kelvins (K), 0.01 °C).

Answer 2

To calibrate a thermometer in Celsius, you will need to place it in a container of ice water and ensure the thermometer reads 0°C. Then, move the thermometer to boiling water and check that it reads 100°C, adjusting if necessary. Repeat these steps until the thermometer is accurately calibrated.