Computational Thinking (How to think like a computer scientist) Lesson 3 Abstraction

Objectives To know the term ‘Abstraction’ means Identify a use for abstraction in an algorithm

Recap - The four cornerstones of Computer Science  

What is Abstraction? Abstraction is one of the four priciples of Computer Science.  Abstraction means to hide unnecessary detail To draw a cat, we do need to know that it has a tail, fur and eyes. These characteristics are relevant. We don't need to know what sound a cat makes or that it likes fish. These characteristics are irrelevant and can be filtered out. We don't need to know what size and colour these are. These specifics can be filtered out

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Describing Algorithms There are two ways of describing an algorithm: Flowcharts – A graphical representation of the steps involved Pseudocode – English like instructions detailing every step

Abstraction in Use In the last lesson you decomposed the problem of drawing the house into a series of smaller problems House Draw Chimney Door Windows Outline

Drawing a Window The abstraction for a window in this house is that it is square and has glazing bars which divide the window into 4 panes The abstraction is not concerned about where the window is placed in the building

Activity 2 – Drawing the Windows What other abstractions can you identify?

Houses