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Magnetism & Electricity
What you should know.
- The end of a magnet that
points north is called the north-pole (N). The Earth has a magnetic field
around it.
- Two N-poles (or two
S-poles) repel each other. An N-pole and an S-pole attract each other.
- Iron and steel can
magnetised by stroking with a magnet. Iron and steel can be demagnetised by
heating to 'red heat'.
- Magnets are used in
cupboard catches, compasses, magnetic cranes and hospitals.
- An electromagnet is made
from coil of wire connected to a battery. It can be switched on and
off.
- For an electric current
to flow there must be a complete circuit.
- A conductor lets a
current easily. An insulator does not allow current to flow.
- An electric current is
the flow of electrons.
- If 2 bulbs are in series
the same current flows through each bulb.
- In a parallel circuit
there is more than one path. Some of the electrons travel along each path.
- The thin wire in a light
bulb glows white-hot because it has a resistance to the current.
- A conductor has a low
resistance, an insulator has a high resistance.
- An ammeter measures the
size of a current, in amps (A). An ammeter is always connected in series.
- A fuse is a weak link in
a circuit. It breaks if the current is too high.
- in a mains plug the live
wire is brown, the neutral wire is blue and the earth wire is green/yellow.
- A battery stores energy.
It can push electrons around a circuit. The size of the push is measured in
volts (V) using a voltmeter.
What you should be able to
do.
- Make a magnetic game and
explain how it works.
- Find the shape of a
magnetic field using iron filings.
- Plot the shape of a
magnetic field using a plotting compass.
- Connect up a circuit with
a switch to light a bulb.
- Draw a circuit diagram
using the correct symbols for a battery (or cell), a lamp and a switch.
- Explain how a switch
works.
- Use an electric to test
whether materials are conductors or insulators.
- Connect up a circuit with
2 bulbs in series.
- Connect up a circuit with
2 bulbs in parallel.
- Analyse a circuit to
decide which switches are needed to light a bulb.
- Use a variable resistor
to control the brightness of a bulb.
- Connect a ammeter into a
circuit correctly.
- Read the scale on an
ammeter correctly.
- Investigate the heating
effect of electricity on a thin wire.
- Connect voltmeter to a
battery.
- Investigate a battery
made by pushing two different metals into a fruit.
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