Method- I got all my apparatus out and then I connected the wires up to the variable resistor and the voltmeter and then I connected this all up to the power pack and also to the electromagnet. When I was doing the experiment I first changed the amount of coils and would see if this would affect the amount of paper clips being picked up. On the second experiment I changed the volts and would see if this would affect the amount of staples being picked up.
Diagram-
Fair Test-
- Make sure that use the same amount of iron filings
- Ammeter reading is correct as possible
- Try to make exact number of Coil numbers (e.g. no bent wires etc)
- Same amount of wire as the resistance of it can vary the results from each other.
Scientific explanation- When insulated wire is wrapped round an iron core and the ends of the wire are connected to a power pack the core becomes capable of picking up paper clips and staples. This is called an electromagnet. The nail is magnetised by the current in the wire. If the battery is disconnected then the iron clips will fall off. This is because most of the magnetism has been lost.
The passage of an electric current along a wire creates a magnetic field around the core. The fields are in the shape of a series of concentric rings. The more coils used in the electromagnet, the stronger the magnet is. If there is one coil, and another is added, then the two coils have twice the strength of one. This is because the current going through the wire makes the iron core the factor that induces electromagnetism, as so when there is more current, there will be more wire or a more magnetised core.
Magnets were formed when certain molten metals, (iron, nickel and cobalt,) cool. Normally when the atoms in a non-magnetic crystallise, the atoms point in random directions. But because of the properties of the metals mentioned, these atoms line up into parts of the magnetic with similar directions called domains. This is because the earth has a magnetic field, and the atoms in the metal all follow these magnetic lines and form these domains. This is similar to what happens when an electromagnet is formed.
Bibliography- I used the Internet and my science book to help me with my planning. The sites I used was the BBC homework help site just so I can understand fully what is meant by electromagnetism.
Results- (first experiment changed coils, kept current the same)
Results- (second experiment changed current, kept coils the same)
(Only a maximum of 4 amps for both experiments)
Conclusion- I found out that the more coils wrapped around the iron core the more paper clips got picked up and the bigger the current going into the iron core the more paper clips got picked up this matched my prediction, apart from on the second experiment when 3.5 amps was going into the iron core it only picked up 9 paper clips this is a strange result but maybe I didn’t have 10 coils on the iron core this could have easily affected it.
Evaluation- I didn’t experience any problems as such but maybe next time I will keep other variables constant for example the size of staples used or the weight of the stables. I couldn’t look into electromagnetism in a lot more detail.
Oliver Minton 10JL
