• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Electromagnets Investigation

Extracts from this document...





An electromagnet is a device consisting of a solenoid usually a cylindrical coil of insulated wire in which an iron core is placed. An electric current passed through the coil induces a strong magnetic field along the axis of the helix. When the iron core is placed in this field, microscopic domains that can be considered small permanent magnets in the iron align themselves in the direction of the field, thus increasing greatly the strength of the magnetic field produced by the solenoid. The magnetization of the core reaches saturation once all the domains are completely aligned, and an increase of the current in the solenoid has little further effect. When the current is switched off, the core retains only a weak residual magnetism.

The Domain Theory

The domain theory of magnetism suggests that a magnetic material such as iron contains within its structure tiny cells called domains and that mini molecular magnet exist inside theses domains.

In an unmagnetised piece of iron all the mini magnets within a particular domain point in the same direction but in each neighbouring domain they point in different directions. The result of this is that the magnetised effect of the domains cancel each other out.


In an unmagnetised piece of iron all the domains are lined up so that their magnetic effect reinforce each other.


Flemming’s left hand rule

Using Flemming’s left hand rule the direction of the force/motion can be predicted


...read more.


  1. Set up the experiment as shown on the diagram
  2. Get the nail and put 5 coils around it.
  3. Switch the power pack on and put it on 2 amps.
  4. Take the nail and put it near the paper clips.
  5. The nail should attract the paper clips towards it.
  6. Switch the power pack off and count the number of paper clips caught.
  7. Record the result and do the same for 4, 6, 8, 10, and 12 amps.
  8. Repeat the whole experiment another two times to make the results accurate by making an average..


For this experiment to be fair, I need to consider a few things:

  • Keep the number of turns the same when I am doing the experiment for the current.
  • Keep the current the same when doing the experiment for the number of turns.


Safety is a major aspect to any experiment:


I will use two different tables for the two variables; number of coils and the current.

Number of Paper Clips Caught

1st results

2nd results

3rd results


Number of Coils

5 coils

10 coils

15 coils

20 coils

25 coils

Number of Paper Clips Caught

1st results

2nd results

3rd results


Current (Amps)








I am going to repeat the experiment at three times. This is so it will enable me to make an average time.

...read more.


The way I did the experiment was that I put turns of coils on the iron nail and connect the wires to a power pack. I then took the nail near to some paper clips which attracted to the nail:


Using paperclips is not a good way of doing this kind of experiment because it takes time to count them, and you may miscount. So, if I had the opportunity to do the experiment again I will use iron fillings instead of paperclips. This method will not only be quick but also accurate because when you take the electromagnet near the iron fillings, it will attract them and you only have to weigh them, instead of counting.

To improve the experiment even more I could use a soft steel core instead of an iron core. This will improve the experiment because it will make sure that the core isn’t remained magnetically charged from the previous experiment, and so doesn’t produce any anomalous results.

I could also extend the experiment and see if the cross-sectional area of the coil effect the electromagnet. This could be done by………………………………………………

I also could also repeat the experiment four times instead of three, which will make the results eve more accurate, when making the average, which can be done by adding the four results and dividing the answer by four.

...read more.

This student written piece of work is one of many that can be found in our AS and A Level Fields & Forces section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Fields & Forces essays

  1. Peer reviewed

    Investigate four factors that may affect the strength for electromagnets: the number of turns, ...

    4 star(s)

    Distance between the sensor and the magnet at t=23.4�C with 40 turns Strength of magnet/T Distance X1 X2 X3 X4 X5 5 38.5 39.6 37.3 37.9 38.2 10 32.8 31.9 32.5 33.8 33.2 15 30.3 28.7 30.4 29.5 27.5 20 26.5 28.8 29.3 27.2 27.6 25 22.5 22.6 21.9 23.2

  2. How does the number of coils on an electromagnet affect its strength?

    The electromagnet will become stronger if we add more coils because there are more field lines in a loop then there is in a straight piece of wire. In a solenoid there are a lot of loops and they are concentrated in the middle, as more loops are added the field lines get larger, therefore making the electromagnet stronger.

  1. Investigation to determine the viscosity of glycerol.

    Buoyancy: "The upthrust is equal to the weight of the displaced fluid. "8 Viscous force: "Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction."9 Upthrust and viscosity balances the weight of the sphere and when this happens the object is said to have reached terminal velocity.

  2. What Affects the Strength of Magnetism Exerted By an Electromagnet?

    Why is a Magnetic Field produced due to the flow of a current? Electric currents and magnetic fields are deeply related. An electron, or any other charged particle, placed in a magnetic field will move as a result that field inflicting its magnetism.

  1. Maglev Trains And The Technology Behind Them (magnetism)

    This is why they are used as the core of the electromagnet. The picture below explains the way in which the EMS system levitates the train. This picture shows the electromagnets of the train being attracted to the electromagnetic rail above and that by finding the right balance between the

  2. Investigate the factors affecting the induced e.m.f. in a coil due to the changing ...

    is also decreased. CONCLUSIONS The induced e.m.f can be affected in five ways. Through the investigations, it can be concluded that the induced e.m.f. is directly proportional to (a) the changing magnetic field in a neighbouring coil and rate of change of magnetic field (frequency of A.C.

  1. Investigation into the factors affecting the strength of electromagnets - Planning Experimental Procedures.

    of the copper wire at the start had to be 2m long. I also took some readings which gave a correct pattern of results, therefore I decided to use the same method of doing the actual experiment. The magnetic field around a wire is circular and this field weakens as you move away from the wire as shown below.

  2. Investigating a factor affecting the voltage output of a transformer.

    I found that with nominal voltages greater than 4Vm, the power supply trips after about five seconds, and so I shall take all my readings after ten seconds, and while this may not give accurate results, it should obtain ones reliable relative to each other.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work