BuiltWithNOF
Electricity 2

Finding out about materials

We can find out lots about materials by using our senses of sight, touch, smell and hearing. For example a material might be transparent or be a certain colour. It might feel cold or smooth to touch. It might have a special smell - like wood. It might make a ringing sound when struck. Simple investigations using our senses tell us a great deal about the special characteristics or properties of materials.

Some properties of materials can only be investigated if we use special equipment rather than just our senses. For example we can try the effect of a magnet on a variety of materials. Similarly we could try the effect of electricity on the materials. For this we will need a circuit.

elec circ 2 testing cond ins labelled

The circuit has a gap in it so the bulb will not light up.

What might happen if we connect a piece of a material in the gap using the crocodile clips to attach it?

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Set up a simple circuit containing a battery, bulb, switch and connecting wires. Check that the bulb works then make a gap in the circuit with crocodile clip wires so that they can be connected to samples of different materials.

Scientists work in a neat and ordered way so donít clutter things up by trying lots of materials at the same time.

Try one material at a time.

Choose one piece.

Write the name of the material.

Join into the circuit in the gap.

Switch on.

Write down if the bulb turns on or remains off.

Name of material or object

Does the bulb light up or not?

 

 

Look at the next two photographs. What observations can you make and what will you write in the results table?

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Is silver paper made from real silver or is it just paper which is a silvery colour?

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The answer is that itís not silver and itís not paper either! In fact itís silly calling it silver paper because itís really called......
                                                               Aluminium foil

Do you think the bulb will light up when we try the aluminium foil in our circuit?

Electrical wires or cables are made from two different materials. What are they and why is each one equally important in making a cable?

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The photographs above show a pair of pliers which have been used to pull the copper wire out from the plastic sleeve or covering surrounding it. We can test the two materials separately to find out if electricity will pass through them.
What is happening in the right hand photograph?
What do you think will happen if the blue plastic covering from the wire is tried in the circuit?

The materials which allow the bulb to light up must be allowing electricity from the battery to pass through them and travel around the circuit. They make the circuit complete and we give them a special name - CONDUCTORS of electricity.
The materials which do not allow electricity to pass through them are called
INSULATORS.

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With our knowledge of conductors and insulators we can design, make and even invent electrical gadgets or games.

Which popular game uses a long bare metal wire and short bare metal wire which are bent into special shapes?

Buzz off!

You can use the bulb to make the silent version of the game but a buzzer in place of the bulb is more fun!

This game uses conductors and insulators but where are they and why do we need both?

Another very popular game which uses an electrical circuit is OPERATION.

These photographs show what you need but how do you make the game?

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Perhaps you could invent a new type of buzzer game based upon this simple circuit and your knowledge of conductors and insulators. If you are successful and become a millionaire then please get in touch!!!