u/FingerAccurate7102

Reading posts on r/metric I found intresting that many redditors here hate tonne.

Tonne (A.K.A. metric ton) is a unit of mass equivalent to 1 000 kg it's legal to use in SI.

The point that tonne-haters make against the tonne is that tonne is equal to megagram, so this unit is useless.

I'm not a tonne-hater, I sometimes use tonne for big numbers of mass and here are some points to defend the tonne

1. Tonne is more understable.

As first Polish dictionary would describe it "everybody see what is a tonne" Tonne is useful in describing huge amounts of mass and many more people knows what is a tonne than what is a megagram. You can also add prefixes to tonne, to make the mass even bigger and the same as many more people knows tonne but not megagram, many more people know what megatonne is, rather than teragram. So tonne is useful if we want to make your work easier to understand for "the rest of the world".

2. Agriculture and quintal replacement.

In agriculture there is a unit called "quintal" which is equal to 100 kg, but it isn't legal unit in SI system, quintals are used by farmers, because they are big enough to give smaller numbers than kg, but small enough to give more precise numbers than Mg. As quintal isn't legal, it was replaced with "decitonne" (deci + tonne) so tonne is useful in agriculture. (Yes, SI could just legalize Quintal or make 10^(5) prefix, but still in modern SI it's the only way to use 100 kg units)

What do you think? What are your reason to like/dislike the tonne?

1st space after unit

You should type a space between the number and the unit. For example: 315 kg instead of 315kg, but also 20 °C instead of 20°C.

2nd Volume

Litre isn't actually the unit of volume in SI, the cubic metre is. Litre is allowed to used, but not the SI unit, 1 L = 10^-3 m³. Also don't mess the conversion, 1 m³ = 1 000 dm³ not 10. The difference is also cubed. Back to litre, both lowercase and upper case "L" are allowed as its symbol, so both 10 L and 10 l are correct

3rd lowercase

You aren't supposed to write the units with capital first letter even if the symbol is capital. For example 1 Mg is megagram, not Megagram and 1 J is joule, not Joule.

4rd hectares

Hectare (ha) is not SI, SI-allowed unit of area. 1 ha is equivalent to 10⁴ m² or 1 hm². It sounds like a unit with a prefix (hecto-are) but it's officially not (it was defined as 100 ares, but in SI it is an independent unit), "are" is a different unit allowed in SI. Hectare was originally based on are but officially it's not an are with a prefix. As hectare doesn't officially have a prefix you theoretically can make abominations like "kilohectare" but it's almost never used and I don't recommend them.

5th temperature

It's more known fact than the others but the unit of temperature is actually called kelvin, not degree Kelvin, so there is 303.15 kelvins outside, not 303.15 degrees kelvin. So don't make that mistake. Kelvin is the same as degree Celsius, so if the temperature is raised up 1 K is also raised up 1 °C, the only difference is 0 where 0 K is absolute 0 (-273.15 °C) and 0 °C is water freezing temperature in 1013 hPa so 273.15 K. Also you can add prefixes to K and even °C, so 100 K being 1 hK or 1000 °C being 1 k°C is actually legal, but not usually used especially for degrees Celsius.