Simulation - A Practical Guide to Teaching Computing and ICT in the Secondary School - page 109

more readily promote an understanding of the relationship between parts. Both
approaches should be employed as part of a strategy to encourage incremental or
scaffolded learning. For example, pupils who use computer Modelling to explore
the relationship between the components in an electrical switching circuit may be
able, at some point, to design and test their own virtual circuits.
Modelling can imitate some part of an event or activity quite effectively, but how
well the event or activity has been broken down into its component parts, and the
quality of the information fed in, will significantly affect its workings and any
resulting outcome. The phrase 'Garbage In Garbage Out' (GIGO) is quite widely
used in relationship to this phenomenon. A dramatic example of the interdependency
of parts of a model is illustrated by the work of some high school students in
Arizona, on leaf shrinkage. The fossilised leaf record was used partly by climate
scientists to determine weather patterns in the past. Larger leaves were regarded as
an indication of warmer periods (significant growth) and smaller ones as an
indication of cooler periods. Shrinkage as a result of the drying-out process was
considered to be a negligible feature. The students were able to prove that this was
incorrect. Leaves do shrink much more than was previously thought when they
dry out. Their discovery is now factored into climate models, thus making them
more accurate ( see Resources: Leaf Shrinkage). A general principle that pupils need
to be made aware of is that the likelihood of error increases exponentially as the
scale and connections between parts multiplies.
Teaching computer Modelling in schools can be achieved using a broad spectrum
of tools that range from spreadsheets and algorithms, to the virtual worlds offered
through gaming. The particular nature of spreadsheets makes them very valuable.
Spreadsheets first emerged in 1979, for use with personal computers in the form of
VisiCalc; an application designed to help with accounting tasks. The original
concept of a simple array of rows and columns through which data can be updated
automatically has been continually extended to now include:
… libraries of mathematical and statistical functions, versatile graphing and
charting facilities, powerful add-ins such as Microsoft Excel's Solver, attractive
and highly functional graphical user interfaces, and the ability to write custom
code in languages such as Microsoft's Visual Basic for Applications.
(Baker and Sugden, 2007, Abstract)
It is probably accurate to state that when Dan Bricklin, a MIT graduate, created
VisiCalc, he could not have anticipated how all-pervasive its successors would
become. However, the basic idea 'has stood the test of time; indeed it is nowadays
an indispensable item of software, not only in business and in the home, but also
in academe' (Baker and Sugden, 2007, Abstract).
Spreadsheets are enormously flexible and relatively easy to use. They require the
application of Computational Thinking. Pupils must engage in Abstract Reasoning
and Pattern Recognition and make rules to employ them properly ( see Resources:
Modelling). They can be employed to investigate and test activities and events, and
readily support the dreaded 'what if' question. They enable direct links with
mathematical Modelling and programming to be made by pupils. And of course,
they are cheap.
There is a section in Chapter 7 on common misconceptions associated with
spreadsheets.