How would you read (pronounce) the ending part of the following sentence:

After purging the measuring chamber with nitrogen gas at a rate of 0.15 L/h the count rate was reduced to 0.021 s–1 x kg–1.

Namely, these symbols are the question: "0.021 s–1 x kg–1". How do you read them correctly?

  • 2
    If no mathematician, but I would read it as "to the negative 1". Commented Apr 23, 2021 at 8:15
  • 2
    I would read that as 0.021 per second per kilo. If you do want to read it a a power then to the minus one is usual.
    – mdewey
    Commented Apr 23, 2021 at 11:02
  • @Natalie you're welcome.Btw, I just noticed my typo there, *I'm no mathematician. Commented Apr 23, 2021 at 11:20
  • You should post your question on the physics site.
    – Lambie
    Commented Apr 23, 2021 at 15:37
  • 1
    Related: chemistry.stackexchange.com/q/18700. Coming from an engineering background, in common/casual usage I might say "sec-negative-one times kilos-negative-one." More correctly, I would say "per second per kilo" as @mdewey suggested.
    – randomhead
    Commented Apr 23, 2021 at 15:53

1 Answer 1


Generally you wouldn't read these out loud. And if you are reading to yourself you don't need to say anything, you can just have the visual or textual impression.

However if you do need to speak it out loud, you use "per"

The count rate was 0.021 *per second per kilogram"

And s-2 can be read as "per second squared" or "per second per second".

A Joule is one kilogram meter-squared per second-squared (kg m2 s-2)

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .