Extract from Computer Science in the National Curriculum ebook
When pupils start to learn about algorithms, real world contexts are much more likely to be accessible than abstract computational problems - think about the steps a child might follow to get ready for school in the morning or to prepare a sandwich. Breaking down a task into a sequence of steps is at the heart of algorithmic thinking. It’s easy enough to draw pictures to illustrate this, or to jot down sentences to describe the various steps, but it’s fun working with digital media here too. Taking a collection of jumbled up photos in PowerPoint or sentences in Word and using drag and drop editing to get the steps into the right sequence provides an easy way in. Alternatively, you could video yourself or a pupil following a recipe, TV cookery programmes being a genre with which many children will be familiar. Import the footage to MovieMaker, then split into clips and jumble the order up on the time-line, setting pupils the challenge of reassembling the clips into the right sequence.
The idea of selection in algorithms, such as that of ‘if ... then .... else ...’ rules, can be explored through PowerPoint too, using two or more hyper-links on slides to link to other slides in a non-linear deck. For example, pupils can quickly develop a simple ‘choose your own adventure’ game by creating a branching story, each scene written or illustrated on its own slide, with choices presented as hyper-linked options, with the next slide determined according to whichever option is clicked.The same idea could be used to model biological classification keys (or ‘branching databases’ as in the old QCA scheme of work), with successive questions displayed according to the answers clicked on preceding slides. Getting pupils to think about the branching, typically binary, tree structure underpinning decks like these leads into interesting, and quite subtle ideas about formal data structures.
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