UnitsIQ is efunda's iPhone version of its online unit conversion utilities. It features 927 scientific and engineering units in 78 categories, including hardness, wire, and sheet metal gage units. App Store
This temperature scale was invented by the Swedish astronomer Anders Celsius in 1742. The scale is based on 0° for the freezing point of pure water and 100° for the boiling point, with the interval being divided into 100 parts. The scale is sometimes called the centigrade scale because of the 100-degree interval between the defined points.