"Conductors & Insulators" Return to list of pracs

Aim: This activity is used to identify what materials are conductors and what are insulators.

Equipment: The equipment includes...  

• three wires;
• One 9V, C or D size battery;
• masking tape;
• globe;
• a selection of materials: straws, pencils, pens, zips, pencil cases, steel wool, cotton wool, icy pole sticks, aluminium foil etc.

Method: Pose the question ... "Will all materials let electricity pass through them?" Get them to suggest ways to test if a material will allow electricity to pass through it. Tape with masking tape one end of one wire to the base of the battery. Tape one end of the another piece of wire to the top of the battery. Attach with masking tape the end of top wire to the metal casing of the globe. Tape a third piece of wire to the very base of the globe. The two open ended wires can be connected across materials to see if they are conductors or insulators. They will conduct electricity if they are conductors and the globe will therefore glow!

Background knowledge: Good conductors of electricity require the material to allow charged particles to move freely through its structure. If charged particles (negatively charged electrons) cannot move easily through the material, then it is called an insulator. This is why wires are made of metal which as you have discovered are generally very good conductors. It is in the nature of metals to allow free moving electrons to move throughout its structure very easily. The electricity passes out of the base of the battery through the wire to the base of the globe, through the filament in the globe. Only if the material can conduct electricity will the globe light up also.

Get students to make predictions and then test their predictions.