Clarification details
Updated November 2015. This document has been updated in its entirety to address new issues that have arisen from moderation.
Definition of a complex machine
Explanatory Note 3 defines a complex system as being a machine with an internal energy system, and levers, inclined planes and/or screws working together to enable the machine to perform its intended function(s).
The internal energy system could be an electric motor, a steam engine, a turbine, a combustion engine or a solar energy system that combines with levers, inclined planes and/or screws to enable the machine to perform their intended function(s).
General Notes
When explaining how a machine works, students would generally refer to the processes it performs. For example, a student could refer to a specific product that is produced by the machine and explain how the machine enables creation of the product.
Students need to also refer to the components used and discuss how they work in relation to other components and allow the machine to function.
Evaluating the energy efficiency of a complex machine (as required for Merit) may require students to examine and compare with another but similar complex machine, having a different internal energy system. Such an activity could lead into a discussion and justification of possible ways of increasing a machine’s energy efficiency (as is required for Excellence).