I don't have a reference, but I was taught, and people I talk with, only
use singular when the number is one. I would even use plural if there
are decimal zeros after the one. I think it has more to do with
mentally reading it or saying it than with printing it.
Examples:
1 volt
one volt
1.00 volts
zero volts
0.0 volts
Although I understand Hugh Haskell's suggestion of not mentioning the
unit if the value is zero, I think it is always best to specify the
unit. (1) It's an easy rule... always use units. (2) It gives an
indication of what type of meter or scale was being used. I think we
can infer different things from the following measurements: zero volts,
zero millivolts, zero kilovolts. (3) It confirms the student (or
speaker/writer) knows what's going on. If the student says, "I measured
the potential and got zero amps," then I know something isn't right.
Maybe they just mixed up the units, but in my lab, they most likely
wanted to measure potential, put the meter on a current range, blew the
meter fuse, and got a reading of zero amps.
Michael D. Edmiston, Ph.D.
Professor of Physics and Chemistry
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu