Computing KS2: Decomposition

This short film explains how decomposition involves breaking one big problem down into smaller, more manageable problems that can be tackled step by step.

Decomposition is explored further by looking at the example of an imaginary Stone Age character working out how to cook mammoth steaks over a fire.

She has to work out how to start the fire, keep it from spreading and how to cook the meat safely. We see her working through the problems as she decomposes the big problem and tackles each smaller problem in turn.

The film then looks at how a complex task like making a computer game can be broken down into smaller tasks such as deciding on a setting, making the characters, working out the game play, adding the music, etc. We then see how these smaller elements are combined to make the final, complex outcome.

Finally, the film discusses how decomposition is used to break down large and complex real world problems like controlling traffic, into smaller problems that can be solved using different types of computer systems working together.

This short film is from the BBC Teach series, Cracking Computing.

Teaching Notes

Decomposition can be introduced by looking at familiar everyday problems and breaking them down into smaller problems, using flow charts and diagrams to identify the smaller tasks needed to achieve the larger outcome.

When pupils are working on developing their programming skills by writing algorithms and then creating programs, decomposition is an important skill that they will need to use as they start to learn how to turn their ideas into functional programs.

Modelling and demonstrating ways to do this - using pencil and paper notes, discussion with classmates, drawing diagrams, flow charts, lists, etc. - will help to ensure that the idea of decomposition is an integral part of the programming process from the start.

Other subjects

Maths: Decomposition is a familiar aspect of calculation in the maths curriculum and the process can be compared to the idea of decomposition when programming as they are using the same concepts.

Design & technology: The design process, working out how to fulfill a brief and deliver a functional product, is also similar to the development of a computer program and the concept of decomposition can be useful when applied here.

Curriculum Notes

This short film is suitable for teaching:

  • KS2 computing curriculum in England
  • Technologies curriculum area at 2nd Level in Scotland
  • KS2 digital competence framework in Wales
  • KS2 using ICT cross-curricular skill in Northern Ireland

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Working with data