- Say what you did; do not give directions for doing it, as in a
- The past tense is best for describing what you did.
- Use correct symbols, not spelled-out Greek letters, etc. Hand-write
them if necessary.
- All measurements should have errors and units. Exceptions are when the
error is negligible, which should be commented upon, and, for example, the
g-factor, which is dimensionless. The typical form for giving a measured
value is: (3.5 ± 0.3)x103 cm.
- Give only as many significant figures as are consistent with the error
on a value.
- Poisson errors are only correct for counting quantities. In most
fitting programs, the calculation of Poisson errors is only correct if the
y-value is the actual count, not counts divided by time, or average
- Generally, give data as a plot, not as a table of values. The data
should be represented by points with error bars, while the theory or fitted
function should be given as a curve. Axes should be labelled with the
name of the quantity and the units, in parenthesis. "Time delay (ns)"
- Don't usually refer to computers or computer programs. Refer to the
method instead ("chi square fit", not "fits program" or "gnuplot").
- Do not put too much detail (such as equipment descriptions) in the
- Do not show the details of calculations in the report; put them in your
lab book and give the final equation, value, etc. In other words, describe the
calculation, but don't do it in the report.
- The names of people used as units begin with a lower case letter if
spelled out but are capitalized if abbreviated (newton, N).
- Compare your results with the previously measured values (usually not
"given" or "known") in terms of your calculated error. If a result
differs from the previously measured value by twice the calculated
error, we say it is off by 2 standard deviations or by 2 s.d. The
difference will be more than 1 s.d. 32% of the time, but more than 2
s.d. only 5% of the time.
- Abbreviations such as PMT should be explained the first time they are
used and are usually given in capital letters. "photomultiplier tube
- Try not to repeat the same word in a sentence or the same phrase in
neighboring sentences. (Repetition cannot always be avoided
in technical writing.)
- Try to write consistently in the same "person". Either use first person
(as in "We measured and recorded the time delay") or third person (as in
"The time delay was measured and recorded"). Don't change between first
and third person too frequently or without reason. Note that third person
writing often requires passive "voice" as in the example above. It is
common in technical writing.
- Use single italic letters, possibly with subscripts, to represent variables
used in your analysis. "We measured the separation of the counters,
NOT "We measured the separation of the counters, dcounter." Units are
written in the regular font (not italics):
- Somewhere in the text you must refer to every figure by number.
Last modified: 30 Dec 2009
(Extensively borrowed from Prof Mike Peters)
Prof. Tom Browder /