SET OF TRIALS
SINGLE
MEASUREMENT
START HERE
Are you finding the uncertainty
(Δx) of a set of trials, or a single
measurement?
NO
Calculate Half of the Range, i.e.
YES
Is Half of the Range larger than the largest uncertainty of a
single measurement?
YES
NO
The uncertainty, Δx, of the
average of the trials is
equal to Half of the Range.
The uncertainty, Δx, of the
average of the trials is
equal to the largest
uncertainty of a single
measurement.
Is the first significant figure
of Δx equal to 1?
YES
Round Δx to two significant
figures.
NO
Round Δx to one significant
figure.
Does the instrument have its
own precision or uncertainty
written somewhere?
Are you using a digital
instrument?
NO
Are you using a stopwatch?
YES
NO
Are you using a ruler,
Vernier calliper,
micrometer or protractor?
YES
The uncertainty in the
measurement is equal to
± 0.1s (due to human
reaction time).
NO
The uncertainty in the
measurement is equal to
± 1.0 of the smallest
division of the instrument.
The uncertainty in the
measurement is equal to
± 1 of the smallest decimal
place displayed.
The uncertainty in the
measurement is equal to
± Half of the smallest
division of the instrument.
Count the number of decimal places in Δx.
Count the number of decimal places in Δx.
Round the average of the trials to the same number of
decimal places as Δx.
Round the measurement to the same number of decimal
places as Δx.
YES