MAXIMUM AND MINIMUM THERMOMETERS

What is the maximum and minimum thermometers? How is it used?

The maximum and minimum thermometers are registering thermometer that can record the maximum and minimum temperatures reached over a while, for example, 24 hours. It is used to record the extremes of temperature , i.e. highest and lowest of a location. A maximum and minimum thermometer measure the daily temperatures to prepare weather reports.

It is also goes by the name of Six’s thermometer, named after its inventor James Six in 1782, and it was commonly used in meteorology and horticulture.

How is the maximum and minimum thermometers used?

It has a U-shaped tube with two separate temperature readings of maximum and minimum temperature.

One bulb, fixed at the top of the arm, contains alcohol, and the other bulb contains a vacuum or low-pressure alcohol vapour.

The alcohol helps to measures the temperature, and the mercury shows the temperature reading on each of the scales.

As the temperature rises, the alcohol in bulb A expands and pushes the mercury below it such that the mercury rises in the other arm.

When the temperature falls, the alcohol in bulb A contracts and the mercury moves towards bulb A.

As the mercury moves towards bulb A or B, it pushes two small steel markers inside the tube, which can be reset using a small magnet.