YEARS 7–12 IDEAS
ARTICLES
FOR THE CLASSROOM
Using Real Data, and Analysing Errors (continued)
or inattention of students). Averaging reduces the size of random
errors but does nothing for systematic errors. These results are
consistent with a systematic error of about 0.1 s in the timings,
which also occurred in other experiments. Electronic timing to
millisecond or better precision could potentially minimise both
the random and systematic errors, which would greatly improve
both the accuracy and precision to which g is found.
as a template for further work. Sources of both systematic and
random errors were examined. In future years this experiment
should improve in both method and results. As a teacher, I am
the summary of all that my students have taught me, so that I can
pass this on to later cohorts.
Auxiliary hypotheses such as the imperfect leveling and the
slightly curved track can be mathematically modeled to examine
systematic errors and improve the fit of the data to the observed
results. In fitting data, it is important to examine the size of the
change to check that it is physically plausible.
Improving this method by straightening the track and controlling
the launch speed of the glider (or using balls rolling down a track)
will be difficult. These problems limit the validity of this method.
Finally, science depends heavily on collaboration with
mathematics, computer modeling, and technically skilled
colleagues. Talk to these people. Share coffee, ideas and books
with them. Then if you are really lucky, they can and will help you
make better experiments.
Summary
This experiment’s unexpected results led to deeper discussion
and analysis of the data. I expect that I am not the only teacher
who has slightly wonky equipment and hope this report serves
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SCIENCE EDUCATIONAL NEWS VOL 67 NO 3