Resources: The handout.
Handout: Handout contains questions related to the Mission Assignment and space for students to draw their diagrams.
Review material on conductors and insulators from KS2. The students should recall that a conductor is a material which allows electricity to flow through it easily, whilst an insulator is a material that does not allow electricity to flow through it easily. Review common conductors and insulators, such as metals and plastic, and discuss the importance of choosing the safest material for different applications.
Ask the students the following question: why do you think car jump leads have a rubber coating on the handle?
Use the presentation to introduce a conductor, insulator and semiconductor. Emphasise the link between the material and resistance so that the students can access the practical. You can demo the practical and introduce the multimeter, including how to set it up. The students can use the handout to help them assess their knowledge of how to use a multimeter and the difference between a conductor, insulator and semiconductor.
Career Film: Take a tour around Rolls Royce SMR's Heritage Museum in Derby to find out about Jason Kouvdos' job. Jason works as the Modelling and Simulation EVP for Rolls Royce SMR.
Expert Film: This is Scott Barham. Scott works as the Chief Design Engineer for Rolls Royce SMR. Listen to Scott as he compares electrical conductors, insulators and semiconductors.
Comparing Resistance Values
The handout lists different materials and their resistance values. The students should compare these and suggest why some materials are more resistant than others by answering questions on the handout.
The Multi-meter
This is a comprehension exercise. The students should read through the information on the handout about the multimeter and then explain why the setting needs to be changed to make certain readings.
Support: The teacher can model the multimeter in a test circuit and test out some different wires in front of the class to show resistance changing between materials.
Challenge: Ask the students to design the perfect semiconductor. Select the material you would use but then describe its features, including shape. Justify your answer.
With their talk partners, ask the students to discuss why physicists in a lab need to know how to use a multimeter correctly in order to stay safe.
An electrical conductor is a material that allows electric current to flow easily.
An electrical insulator is a material that does not allow the electric current to flow easily.
A semi-conductor is a material that has both conducting and insulating properties. The material behaves accordingly depending on the power supply it is connected to. Typically, a high voltage low current will result in conductive behaviour.
It is important that we preface the terms conductor and insulator with electrical, as there are other types of conductor and insulator in physics and this helps to avoid confusion.
Resistivity – this is a physical property of the material that allows current to flow. For example, copper has a low resistivity as it allows current to flow easily, whereas plastics have a very high resistivity as they do not let current flow (they act as an electrical insulator). Resistivity is measured in ohm metres (Ωm).