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

Physics AT1-Resistance of a wire

Extracts from this document...


Physics AT1-Resistance of a wire


The electric current in a solid is a movement of tiny negative charged electrons.  As these electrons move they collide with the particles of the solid which makes the electrons movement difficult.  Resistance is a measure of how difficult it is for the electrons to move.  A high resistance means that the electrons will make lots of collisions and lose lots of energy. The circuit itself can resist the flow of particles if the wires are either very thin or very long. e.g. The filament across an electric bulb is quite thin as needs to resist the flow of particles for the bulb to glow.  Resistance is measured in ohms. The higher the resistance, the lower the current. If there is high resistance, to get the same current a higher voltage will be needed to provide an extra push for the electricity.  Some metals have less resistance than others. Wires are always made out of copper because copper has a low resistance and therefore it is a good conductor. The length and width of a wire also has an effect.

Ohm’s Law: The current is proportional to the voltage, provided the temperature remains constant.


The resistance of a wire depends on certain factors.

...read more.



Where the wire is position I will have a pair of crocodile clips to hold it in place.  I plan to use 70cm of each nichrome wire and I plan to coil each wire.  To help keep my results accurate I plan to only use a low current when testing;  this will keep the temperature of the wire down.  For each wire I plan to take one reading from the voltmeter at a constant current of 0.5 A.   I then plan to repeat the reading of each wire three times and take the average  result .  I shall then be able to calculate the resistance of the wire using the equation resistance = volts/amps and represent this data in the form of a graph.

Fair Test

I have already mentioned which factor I am investigating and which factors I will keep constant (see pages 1 and 2).  I will do the following things to make the experiment a fair test:

  • Use the same material for each wire
  • Use the same length of each wire
  • Take readings using a low current (keeps temp. down)
  • Use same equipment for each test

Safety Precautions

I will take the following precautions and make sure others are safe as well:

  • I will wear safety glasses
  • I will make sure there are no bag or obstacles on the floor causing a hazard
  • I will be careful with the electricity present
  • I will not run around
  • I will not touch live wires



  • Voltmeter
  • Ammeter
  • 2 Crocodile clips
  • 5 nichrome wires (0.28mm, 0.31mm, 0.40mm, 0.45mm, 0.50mm)
  • Power Supply Pack
  • Circuit wires
...read more.


Even though there is a result which doesn’t fit the pattern, the majority of results still follow my prediction.

Improvements and Evaluation

Although I took precautions to ensure this was a fair test, there were some areas where accuracy could have been improved.  The anomalous result suggests that I would need to repeat at least that part of the experiment for that width of wire.  It could be that I didn’t accurately measure out 70 cm of wire or I didn’t read the voltmeter correctly.  However, I think this last explanation is unlikely because I read the voltmeter three times and each time the reading was almost the same (4.2,4.3,4.2).  This suggests to me that the reason for this discrepancy is more likely to be an inaccurate measurement of either the width or length.  There is also the question of whether the current was measured accurately.

Repeating my results more than 3 times would further improve my results and maybe correct the anomaly.  To improve my experiment I should have taken more time making sure wires are correct lengths and thickness.

Further work that could be done is to look at each wire in more detail.  Trying more currents and investigating more factors for example or maybe trying more diameters of wires would be further ideas.


I used the following resources for research:        Physics For You Textbook        

                                                Key Science Physics Textbook        

                                                Time for Physics Textbook

...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. Resistance of a Wire Investigation

    Be careful when the wire is connected, as it will get hot. Be careful when cutting the wire. Make sure the mains to the power supply are switched off when removing the wire from the circuit to be measured. Apparatus Power Supply, Ammeter, Voltmeter, Just over 100cm of E26 Wire, Meter Rule, Two Crocodile Clips, Connecting Wires.

  2. Resistance and Wires

    Test 1 Test 2 Test 3 Mean 0.25 0.26 0.22 0.24 0.35 0.32 0.34 0.34 0.54 0.58 0.58 0.56 0.71 0.69 0.69 0.69 0.88 0.89 0.88 0.88 0.90 0.89 0.90 0.90 1.20 1.19 1.21 1.20 The mean was calculated in the way shown in the calculation: (Test 1 + Test 2 + Test 3)

  1. An in Investigation into the Resistance of a Wire.

    and the temperature also affected the resistance of the wire to make my result more reliable. Although investigating the factor with temperature is very hard because with temperature it's very hard to control the temperature you want it to be.

  2. To investigate how the length (mm) and the cross-sectional (mm2) area of a wire ...

    First of all, for each repetition I performed, I would use a new piece of wire to make sure that the heat generated by the previous experiment did not affect the results. If I had enough resources, I would go one step further and use a new piece of wire for each reading I did to obtain perfect results.

  1. Resistance in a Wire Investigation

    If there are double the atoms, there should theoretically be double the electrons to pass through the wire and hence the resistance will decrease. After my preliminary experiment, I have decided to use 34-gauge wire for the length experiment as it has a bigger range of values for resistance than the 28-gauge wire.

  2. GCSE Physics Resistance of a Wire

    Also if the atoms in the material are closely packed then the electrons will have more frequent collisions and the resistance will increase. 3.Wire length : If the length of the wire is increased then the resistance will also increase as the electrons will have a longer distance to travel and so more collisions will occur.

  1. Coursework for physics - resistance of a wire

    amps in the circuit * Meter ruler-Used to measure length of wire used * Scissors-used to cut the specific length of a wire. * Crocodile clips-to attach the independent variable to the circuit Method: 1) Collect equipment 2) Measure out 50cm of each wire 3)


    Use the Micrometer to measure the thickness of the wire. 3. Using the meter ruler measure out 2m of Constantan wire (Black, 28swg). 4. Cello tape the wire across the 2m ruler. Taught the wire so it is a straight a possible but do not over do it as it possibly could make the wire become thinner.

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