[smnrchrds]

I live in a country with metric system. We use different units of measurement interchangeably because it's easy to do so and we have gotten used to it. I am 1.74m or 174cm tall. The bus stop is 500m or half a kilometer away from my home, etc. While nobody converts 250km to meters, when the value is closer to one, both units of measurement are equally useful and equally used.

Also all physics and engineering formula are designed to get and return metric values. When I see K = 0.5mv^2, I know v is supposed to be m/s and m is in kilograms and the result would be in Joules. If it's E = m*c^2, the same thing could be inferred about it.

I'm curios with all different units of measurement, how do you know when to use which. Is there a convention to always e.g. use ft/s or is it different in each formula?

[riffraff]

Something I never thought about is that there are differences between metric countries too in usage.

E.g. in italy you refer to a glass of 200ml, 100 grams of pasta and two hectograms of parmigiano, while in hungary they routinely use deciliters and decagrams, which I'd never seen outside of school.

[ward]

And the beauty is that you are still able to easily convert it to the type you are used to. I, as a Belgian, might blink once when you use hectogram, but it is trivial to convert it to what I am more used to (say kg or g).

[Ecio78]

And as ward has pointed out, it is so easy to convert between them.

On the other hand I don't understand for examples why in the US they still use measures like "cup", "oz" "pint" in cooking. Should I buy a specifically sized "cup" to cook a us recipe? :)

By watching UK television it seems that even they are using kilograms, liters and also Celsius for oven temperature, and some weeks ago there was a UK famous baker talking with some US guest and saying almost the same thing.

disclaimer: I'm Italian

[achy]

This is exactly why metric is so powerful: I also have no inherent concept of a deciliter or decagram, but I can convert to my understood liter and kilogram in moments.