# Algorithms

Learning Objectives:

1) To understand what algorithms are and why we need them.

2) To know how to use algorithms to draw geometric shapes in Scratch.

Starter: The robot game or SketchBot! (5 mins).

What is an algorithm? It is a sequence of instructions to be carried out until an end point is reached. Think of a food recipe. When you're writing any sort of program, the most important thing is the algorithm - the plan, or design, for what your program is going to do. The algorithm should be written in a language-independent form - flowcharts and pseudocode are common forms used for representing an algorithm. Use Prezi resource.

Discuss whether it would be good if people followed instructions exactly. E.g. what would happen if you pointed to a closed door and said “Go through that door?” Explain that computers work by following lists of instructions, and that they do exactly what the instructions say, even if they are incorrect (or nonsensical).

This lesson explores algorithms for drawing images. This lesson shows the importance of writing and interpreting algorithms correctly. (10 mins)

Development:

Show Big Bang Theory. (2 mins).