This distinction between two major classes of material is basically common sense but we also need to be able to explain it in terms of atoms.

Conduction experiment (courtesy of Sky Learning)

This experiment introduces the students to the types of materials that do and do not conduct electricity. Salt solutions do conduct electricity and this is why the bulb lights up. But sheathing one of the electrodes with a rubber condom prevents any electricity flowing as the rubber acts as an insulator. Remember this as it will be important later!

Exam Tip: All metals conduct; when they're liquid or solid. But just because something isn't made of metal don't assume it won't conduct. The 'lead' in your pencil (graphite, a form of carbon) will also conduct electricity (try it, sharpen both ends of a pencil and put it in a simple circuit). The term 'sea of delocalised electrons' should be used in your exams to any answers relating to the electrical conducting properties of graphite.

Exam Question:

• Referring to the structural arrangement of graphite, explain why graphite conducts electricity and diamond doesn't, even though they are both forms of the same element Carbon.

Watch the Conduction experiment below courtesy of Sky Learning www.skylearning.co.uk