I have to replace imperial units with metric units in a text, and since this is not technical writing , I have to maintain the prose style and clarity.
This is a troubling phrase: "…the air in 1 cubic foot…".
I think I can do that: "…the air in a 30-centimeter cubic region [or cubic volume]…", but since I've seen units being used wrongly before (like saying that 1 cubic foot = 30 cubic centimenters), I would like to have your opinion on this.
BTW: I'm not a native English speaker, nor have I used imperial units daily (my country uses metric).
EDIT: I can't use liters because this is describing a cubic area of space, and 30 liters (or 28 liters) is hard to picture as cube. Take a look at it on another way. When I say "this is a two-feet cubic volume", how big do you think it is in cubic feet?
Also, did you understand the diference between saying "X-feet cubic volume" and "Y cubic feet"?
EDIT2: Here is a new doubt, what is the more correct way of writing this: "the space of a 30-centimeter cube" or "the space of a 30 centimeter cube" (the difference in the hyphen).
Best Answer
If the context shows that "the air in 1 cubic foot" is specifically a cube-shaped volume of air, I would translate it as "the air in a 30-centimeter cube" (or, if greater precision is warranted, a 30.5-centimeter cube or a 30.48-centimeter cube).
If "the air in 1 cubic foot" is simply identifying the size of the volume rather than its shape, I would translate it as "28 liters of air". If 28 seems too precise, you can round it to 30, which overstates the size of a cubic foot by less than 6%.
If you think, as you seem to, that visualizing a cube of the correct size is important, then obviously go with the first option. A 30-centimeter cube is less than 5% smaller than a one-foot cube, so unless high precision is necessary, it's probably a good translation.