GCSE – Lesson 8 – Insertion sort

In this lesson, learners will explore another sorting algorithm, insertion sort. Some exam boards do not require learners to know insertion sort so do check the specification first. They will start by discussing how they would sort objects in real life, which may lead them to describe something akin to an insertion sort. This should be especially apparent when adding a new item to a sorted group of objects.

To begin with, the slides take learners through a broken down version of one pass of an insertion sort that reflects the coded solution introduced in the next lesson. Then the slides will take learners through multiple passes of an insertion sort which is how they will apply the algorithm when executing it on samples of data. Being able to recognise and highlight the sublists at different stages of an insertion sort is essential for showing the individual steps of an insertion sort and will help with understanding the coded implementation next lesson.

Learners will get to practice performing an insertion sort on samples of data of their own which will include a partially worked example to support them with carrying out each pass of the algorithm. Again, words are used instead of numbers in the data samples as this is often what learners struggle more with and therefore need more practice.