Temperature

The Fahrenheit, Celsius and Centigrade are the most common terms of temperature scales. However, these scales have different measurements used for the freezing and boiling points of water and use different sized degrees.

When the thermometer was first invented there was no clear understanding of fixed temperature points. To further confuse the situation, the skills required to make thermometers were not available; it was difficult to make a thermometer with a bore of consistent diameter along its length, meaning that no two thermometers were alike. It was only when people travelled with individual thermometers that they were able to confirm that the fixed points of water boiling and freezing were the same in different locations and the effects of altitude and air pressure were recognised. The boiling and freezing points of water were chosen as fixed points because they were easily achievable.

Although many variations of a thermometer are documented throughout history, the glass thermometer that is most familiar with what we see today was first invented by the Grand Duke of Tuscany, Ferdinand II, in 1654. Although a significant development, his thermometer was inaccurate and predated a standardised scale.

The first recorded thermometer was produced by the Italian Santorio Santorio (1561-1636) who was one of a group of Venetian scientists working at the end of the 16th century. As with many inventions, the thermometer came about through the work of many scientists and was improved upon by many others.