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

Investigating one of the factors that affects the current in a wire.

Extracts from this document...

Introduction

Investigating one of the factors that affects the current in a wire.

In this investigation I will be examining a factor that affects the current in a wire. It is a free choice to what factors I choose to investigate but it must show how it affects the current in a wire and why.

Scientific Knowledge

As any other material metal (wires) consist of millions of atoms. Every atom is surrounded by a number of outer shells.  Each outer shell will contain a number of electrons in it. Depending on the type of material the number of outer shells and the electrons within it will vary.

Metals conduct electricity because they have free flowing electrons. However different metals will have different number of electrons and therefore the conductivity of the metal will vary.

The current travels within the wire by hitting the electrons. Once one of the electrons is hit it moves and hits another. This causes a chain movement we call this free flowing current. The current is pushed by voltage. The higher the voltage the harder the electrons are pushed and therefore the current travels faster. Suppose the distance the electrons have to travel is longer then the electrons will have a harder time moving jumping from one atom to another over a longer distance i.e. there is more resistance.

So if we double the length of a wire, the number of atoms in the wire doubles, so the number of jumps double, so twice the amount of energy is required: There are twice as many jumps if the wire is twice as long.

...read more.

Middle

Pilot Test

I am going to do a pilot test using my lowest and highest results theses are 100mm and 1000mm. The test will show me if my method needs adapting for example whether I will not get a good variation in results so I need to make my highest result higher or my lowest result lower in order to get a better range of results. It also gives me an idea about what results I should be expecting and if I am going the right way around getting them

Pilot Results Table

1st Reading

2nd Reading

Length mm

Voltage (v)

Current (A)

Resistance

Voltage

Current

Resistance

Average Resistance

100

1.07

0.22

4.8

1.03

0.20

5.1

4.9

1000

1.25

0.03

41.6

1.27

0.04

31.75

36.6

As you can see I have got a good range of results on my table. It tells me that my prediction is basically correct because the longer wire compared to the shorter wire has a larger resistance and less current.

I am not going to change anything in the main experiment because I believe that I will get a good range of results and will prove my prediction.

Recording Results

...read more.

Conclusion

Make sure the ammeter is set to 0 when there is 0Amps. Also make sure ammeter can read low values accuratelyThe length of the wire that is relevant is between the crocodile clips because any wire outside the crocodile clips has no current and therefore irrelevant to this experimentMake sure the voltmeter is set to 0 when there is 0volts. Also make sure Voltmeter can read values accurately.Make sure the crocodile clips are powerful and make a good electrical contact with the wire

This also proves that George Ohms law is correct. He defies resistance as:

Resistance property of any object or substance of resisting or opposing the flow of an electrical current. The quantity of resistance in an electric circuit determines the amount of current flowing in the circuit for any given voltage applied to the circuit.

I could expand this experiment by having different cross sections of wire and I could run the experiment at different temperatures. Also I could see how different materials resistance varies. Because metals all have different properties.

II could also find out how much energy is transferred by each coulomb of charge by doing

Power (Watts)  = Current x Voltage (volts)

Or how much electrical charge there is measured in coulombs. One coulomb is the amount of charge passing through a particular point in a circuit each second when the current is one ampere. I could find this out by doing

Charge (coulombs) = current (amperes) x Time (seconds)

                                             I Conclude that the longer the length of wire the higher the resistance will be.

.

...read more.

This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism 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 GCSE Electricity and Magnetism essays

  1. To see how the length of a wire affects its resistance. Im ...

    Length of wire The longer the wire the more difficult it is for electrons to flow through and producing a higher resistance Type of wire In different conductors the ease of flow of electrons is different and so conductors have different resistances.

  2. relationship between voltage and current

    to a table and work out the Resistance using the rearranged formulae; R=V/I * Plot the values of the Current (I) against values of voltage (V) on a graph, this will then tell you the relationship, if its proportional the equation of the line will be Y=X but since this

  1. Electromagnetism - investigating what effect increasing the number of turns in a coil on ...

    * Another important factor I will keep the same is the method I put the weights on the electromagnet, if I put them all on gently instead of dropping them on I will find that my results will be much more accurate.

  2. To investigate how the length of a wire affects the current flowing through it.

    enough range so as too prove difference. Here are the results from my trial run. Results- Length (cm) Current (A) Voltage (V) 0 -0.36 0.02 5 -0.35 0.21 15 -0.32 0.65 25 -0.30 1.06 35 -0.28 1.37 45 -0.27 1.67 55 -0.25 1.94 65 -0.24 2.16 75 -0.22 2.37 85

  1. What Factors affects the resistance of a wire?

    I will then work out the resistance after this. Fixed Variables: (things that I will keep the same) the thing I have chosen to keep the same is the material of the constantan wire to keep the experiment a fair test.

  2. Investigate one or more factors affecting the resistance of metal wires

    * Where I can avoid it, I will not touch the wire while the power supply is switched on or soon after the power supply is switched off because the wire may be hot. However, it is necessary to touch the wire to find out if it is getting hot and so I will do this with caution.

  1. Investigate the factors that affects the resistance of a wire.

    and also make the test fair compared to the equipments that I have for investigating other factors that affect resistance. In order to make this a fair test I would keep all variables except the length of the wire constant.

  2. Investigating one of the four factors, which affects resistance in a wire: Length.

    Therefore the resistance of any material is inversely proportional to its cross sectional area (A): R=1/A However, when talking of length and cross sectional area, it is more common to define the resistance of a material instead of a certain aspect.

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