Anders Celsius

Born in Uppsala, Sweden, in 1701, Anders Celsius showed a talent for mathematics when he was very young. This prowess led to a professorship in astronomy at the early age of 29, in 1730. Celsius was also given to travel – visiting all the notable European observatories of his day. Then in 1736 he traveled with the French astronomer Maupertuis to Tornea, in the northernmost part of Sweden. The goal of this expedition was to determine the correctness of Isaac Newton’s belief that the shape of the earth flattened near the poles. The team confirmed that it did.

This expedition helped make Celsius’s name and catapulted him into more work on geographical and meteorological measurements. His meteorological observations required a precise thermometer, and so Celsius developed a new scale that used as its reference points the boiling point and freezing point of water. He divided the thermometer into 100 degrees between these two points – much as the modern Celsius scale is, but with one exception. Celsius named the boiling point of water 0 and named the freezing point as 100. A thermometer in Celsius’s lab, therefore, looked like an upside-down version of the Celsius scale we use today.