5 minutes

4 Plenary: How a loop can improve the efficiency of a system

Stress that every system is designed for a particular purpose. Some systems are controlled manually (for example, the length of time for which toast is toasted under a grill) and some are controlled automatically (for example, the time for which toast is toasted in an electric toaster).

Ask the class to discuss, in pairs, for 2 minutes, why a loop is an efficient method in the control of a system. For example, instructions have only to be written once; after that, once the system starts, everything happens automatically. The alternative to an efficient control system is that a human being would have to keep checking.

Round off the lesson by reminding the class that, in today’s lesson, they have learned how information from sensors can be used to control events. They have represented instructions in the form of flowcharts and tested whether their flowcharts work.