Information Technology Reference
In-Depth Information
• Algorithms may be decomposed into component parts (procedures), each of
which contains an algorithm.
• Algorithms should be stated without ambiguity, and care and precision are
necessary to avoid errors.
• Algorithms are developed according to a plan and then tested. Algorithms
are corrected if they fail these tests.
• It can be easier to plan, test and correct parts of an algorithm separately.
(CAS, 2012a, p. 13)
As Computing is relatively new, Key Stage Three pupils may not have this
understanding. Even if they have looked at the concepts before, some revision is
helpful. As mentioned in another context, earlier in this chapter, you need to begin
with simple algorithms that relate to everyday events and then move to more
specific and complex examples. The
irst part
of the Royal Institute Christmas
Lecture, 'Ghost in the Machine' (Bishop, 2008), illustrates the concept of a simple
algorithm well. Getting pupils to use or produce algorithms of events, processes
or systems they are familiar with will generate deeper learning and reinforce the
need for precision and order.
There can be more than one algorithm for a particular process. For example, the
stages given in
Appendix 5.1
for creating a pizza can be sequenced in different
ways. An edible pizza (one would hope) would still emerge.
To facilitate Computational Thinking, having identified the alternative
algorithms, the next stage is for pupils to determine which is the best one. Of
course, this may depend on how you define 'best'.
Task 5.8
Algorithms
Design a resource to introduce/recap the idea of an algorithm to Year 7, which
uses a subject area other than Computing.
Often pupils will create algorithms that do not work. It should be stressed that this
is acceptable and reflects what happens in the real world. Algorithms need testing,
'debugging' and refining before we arrive at the most efficient version. This can
be illustrated in an engaging and creative way by using the activity and/or video
'Jambot' (Bagge, 2012).
At Key Stage Three, the Programme of Study for England explicitly states that
pupils need to know 'several key algorithms that reflect computational thinking
[for example, ones for sorting and searching]; use logical reasoning to compare the
utility of alternative algorithms for the same problem' (DfE, 2013).
Task 5.9
Sorting and searching algorithms
Research the key algorithms used by computers for sorting (insert sort, merge
sort, bubble sort, selection sort, quick-sort) and searching. How might you
introduce these algorithms and their uses, in a creative way, to Key Stage Three
pupils?
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