• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10

Resistance of a Wire Investigation

Extracts from this document...


I am going to investigate factors that affect the resistance of a wire. Resistance is measured in ohms. The symbol for an ohm is ?. A resistor has the resistance of one ohm if a voltage of one volt is required to "push" a current of one amp through it. A flow of electricity is a flow of electrons. Imagine a row of electrons, sitting in a wire (for simplicities sake, I will not draw the nuclei). Because we know electrons repel each other, they will spread out as much as possible. Now, suppose an electron is inserted in the left hand end. This would occur if a higher electron pressure were to be at one end than the other, forcing an electron onto the wire. The electrons on the right side force out an electron to the negative positive of the battery. This allows the electrons to spread out and the wire is as before, only the electrons are all one further to the right, and an electron has left the wire. Now, I stated earlier that electricity was a flow of electrons. This means it can be likened to a flow of anything else. As an analogy, I will compare it to a flow of water. The water wheel and the bulb both provide resistance. That is to say they both transform the energy pushing the flow into another sort of energy. Another sort of resistance can be likened to water flowing through a thin pipe. ...read more.


I will not investigate the effects of changing the temperature of the wire as the effects of temperature are small so consequently a large range of values is required, which is difficult to attain in classroom conditions with any degree of accuracy. I will not investigate the effects of the diameter of the wire as few values of this are available to me in school and it involves using different reels of wire which may for example have decayed or tarnished, so a fair test is not absolutely guaranteed. Therefore I am going to investigate the length of the wire as it is easy to vary, uses the same piece of wire and allows easy re-tests, as well as being quantitative so allowing a conclusion to be formed. I did some preliminary testing that showed copper gave such a small resistance that it was difficult to get any accurate results and generate a conclusion. I will use Constantan because it does. Also, room temperature is the easiest to guarantee so I will use that. I found 10 cm a suitable minimum length as any less meant just a small change in length, as little as 1 mm, made, for example, by misaligning the crocodile clips or having kinks in the wire, could lead to large differences in results. Prediction I predict that the resistance of a wire is directly proportional to its length. This is because when current is flowing in a piece of wire, electrons are moving through the ions that constitute the wire. ...read more.


The line shows that seemingly, a zero-length of resistive wire gives a small resistance. This is explained by the equipment; the wires and components used, such as the ammeter and voltmeter, had themselves a small, though by no means negligible, resistance. Although it does not affect the gradient of the graph, it must be noted that the resistance of the wire is actually a small amount less than plotted. Sources of error The experiment was not perfect; for example, the measuring equipment that was used was only accurate to 0.2 units. The equipment itself may also have been slightly un-calibrated or inaccurate. Measurements were taken by eye; this means the angle of the eye may have affected the reading, and human decision affected which value was taken. In addition, the temperature of the wire varied slightly at low lengths and high voltages; they became hot to the touch and at higher voltages actively burned up; this is why lower lengths have fewer readings. This means the averages are less reliable, and the resistance may have been altered by the heat giving nuclei more energy, making them move more, collide with electrons more and thus slow the electrons. The heat originates from the resistance of the wire; electrical energy cannot simply disappear, and this wire converts the electricity to heat energy as it resists. This is more significant in shorter pieces of wire because there is more current passing through each unit of wire, thus there is more energy that can be converted into heat. ?? ?? ?? ?? Martin Smith 1/2 Centre no. 26146 Physics Coursework ...read more.

The above preview is unformatted text

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

    we will have five readings and can then take an average resistance. Then carry out the whole thing again, varying the length of the wire in intervals of 10cm from 10cm to 100cm. To do the thickness experiment, set up the equipment again as shown.

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

    I could also investigate the wires E22 and E24. Main experiment Investigating the factor cross sectional area Diagram = Main power supply = variable resistor = Ammeter = wire = Voltmeter = crocodile clip Method I learnt from my pilot investigation and main experiment for the cross sectional area is

  1. Finding a material's specific heat capacity

    12.0 4926 484 4443 720 26.3 12.0 4926 484 4443 750 26.2 12.0 4926 484 4443 780 26.1 12.0 4926 484 4443 810 26.0 12.0 4926 484 4443 840 25.9 12.0 4926 484 4443 870 25.8 12.0 4926 484 4443 900 25.7 12.1 4926 605 4322 930 25.6 12.1 4926

  2. Resistance in a Wire Investigation

    I was able to get the following results: LENGTH (cm) CURRENT (A) VOLTAGE (V) RESISTANCE (=V/I(�)) 10 0.3 0.13 0.43 15 0.3 0.20 0.66 20 0.3 0.27 0.90 25 0.3 0.35 1.16 30 0.3 0.42 1.40 35 0.3 0.48 1.60 40 0.3 0.57 1.90 45 0.3 0.60 2.00 50 0.3

  1. Physics Coursework Gravity Investigation

    This is more accurate as it doesn't involve estimation. In doing this, one should get 33�5=165 and 66�2.5=165. Both multiplications give a answer of a bounce height of 165cm if the golf was released at 200cm. This would be a sensible prediction of the bounce height when the golf ball was released at a height of 200cm.

  2. To investigate the relationship between the structure and heat provided by combustion of a ...

    the can may vary the results greatly, as it will decide how much of the flames heat is transferred directly to the can and to the water. The experiment should allow the flame to contact the can at its hottest point.

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