Everything Science Grade 10

2.6 CHAPTER 2. CLASSIFICATION OF MATTER

Examples of insulators are plastic and wood.Semi-conductorsbehave like insulators when
they are cold, and like conductors when they are hot. The elements silicon and germanium
are examples of semi-conductors.

General experiment: Electrical conductivity

Aim:

To investigate the electrical conductivity of a number of substances

Apparatus:

• two or three cells


• light bulb


• crocodile clips


• wire leads


• a selection of test substances (e.g.
  a piece of plastic, aluminium can,
  metal pencil sharpener, magnet,
  wood, chalk, cloth).

light bulb

cells

test substance

X

crocodile clip

Method:

1. Set up the circuit as shown above, so that the test substance is held between

the two crocodile clips. The wire leads should be connected to the cells and

the light bulb should also be connected into the circuit.

2. Place the test substances one by one between the crocodile clips and see

what happens to the light bulb. If the light bulb shines it means that current

is flowing and the substance you are testing is anelectrical conductor.

Results:

Record your results in the table below:

46 Chemistry: Matter and Materials