User:Milton Beychok/Sandbox

A tonne (t) or metric tonne (also referred to as a metric ton), is a measurement of mass equal to 1000 kg, or almost exactly the mass of one cubic metre of pure water at 3.98 °C. It is not an SI unit but is accepted for use with the SI.

Using the SI prefixes, the correct SI terminology for a tonne would be a megagram (Mg) but this term is not often used. In most countries, tonne is used as the standard terminology for the metric mass measurement.

Origin

There does not appear to be a definitive concensus as to the origin or etymology of the word tonne. Most sources indicate that it has a Celtic or Gaelic origin that led to the Latin word tunna and then to the words tun and tonne in French and English. In the evolution of both of those languages, tun and tonne originally referred to a a barrel or cask with a volume of about 954 litres (almost a cubic metre), which for wine, beer and many commonly used aqueous solutions would weigh about a tonne.

Conversions

One tonne is equivalent to:

• One megagram (exactly);
  • This is the official SI term, but not generally used in industry, in shipping nor colloquially
• Template:Frac pounds (exactly by definition), giving approximately
  • 2204.622 621 848 775 807 lb (to 19 significant digits)
  • 2204.622 622 lb (to ten significant digits)—an easy-to-remember figure
  • 2205 lb (to four significant digits)
• 98.44% of a long ton
  • One long ton (2240 lb) is 101.605% of a tonne
• 110.23% of a short ton
  • One short ton (2000 lb) is 90.72% of a tonne
• 32,150.75 troy ounces