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

Investigating the factors affecting the resistance in a piece of wire.

Extracts from this document...

Introduction

Helen Bewick 10C

Investigating the factors affecting the resistance in a piece of wire

Planning

Resistance- Resistance is a force which opposes the flow of an electric current around a circuit so that energy is required to push the charged particles around the circuit. Resistance is measured in ohms.

During this experiment I aim to research and plan an experiment to investigate a factor that affects the resistance in a piece of wire.

The possible factors I could change in this investigation are:

  1. Length of the wire,
  1. Thickness of the wire,
  1. Type of metal- Copper, Nichrome and constantan
  1. Shape of the wire,
  1. Temperature of the wire,
  1. Density of the metal.

I have chosen to investigate the length of the wire because length is a continuous variable with a continuous range so I will be able to choose any lengths to investigate.

I chose not to investigate thickness because although it is a continuous variable the wires available to me only come in set thickness that do not go up in regular intervals.

I chose not to investigate type of metal because it is not a continuous variable so I would not be able to evaluate the investigation by linking two or more groups of data on a graph.

I chose not to investigate the shape of the metal because it isn’t a continuous range. I could only use two options bent or straight.

I chose not to investigate the temperature because although it is a continuous range it is very difficult to maintain a temperature, as you couldn’t use a water bath because of safety aspects. It is also difficult to measure the temperature of a piece of wire.

...read more.

Middle

The resistivity of Nichrome at 250C is 100 x 10-8 ohm-m. The radius of the wire is 0.00014m2. To find the area of a cross section of the wire i use the equation for the area of circle

Area of circle = πr2

Area of circle  = π x 0.000142

Area of circle = 6.16m2 x10 -8

Working to find the resistance

To predict resistance for a length of wire of 10cm I use the equation,

Resistance  = resistivity x length / area of cross section of the wire

Resistance = 100 x 10-8 x 0.1m / 6.16m2 x 10 –8

Resistance = 1.62 Ω rounded 2 d.p.

To predict resistance for a length of wire of 20cm I use the equation,

Resistance  = resistivity x length / area of cross section of the wire

Resistance = 100 x 10-8 x 0.2m / 6.16m2 x 10 –8

Resistance = 3.25 Ω rounded 2 d.p

To predict resistance for a length of wire of 30cm I use the equation,

Resistance  = resistivity x length / area of cross section of the wire

Resistance = 100 x 10-8 x 0.3m / 6.16m2 x 10 –8

Resistance = 4.87 Ω rounded 2 d.p

To predict resistance for a length of wire of 40cm I use the equation,

Resistance  = resistivity x length / area of cross section of the wire

Resistance = 100 x 10-8 x 0.4m / 6.16m2 x 10 –8

Resistance = 6.49 Ω rounded 2 d.p

To predict resistance for a length of wire of 50cm I use the equation,

Resistance  = resistivity x length / area of cross section of the wire

Resistance = 100 x 10-8 x 0.5m / 6.16m2 x 10 –8

Resistance = 8.12 Ω rounded 2 d.p

To predict resistance for a length of wire of 60cm I use the equation,

Resistance  = resistivity x length / area of cross section of the wire

Resistance = 100 x 10-8 x 0.6m / 6.16m2 x 10 –8

Resistance = 9.74 Ω rounded 2 d.p

To predict resistance for a length of wire of 70cm I use the equation,

Resistance  = resistivity x length / area of cross section of the wire

Resistance = 100 x 10-8 x 0.7m / 6.16m2 x 10 –8

Resistance = 11.36 Ω rounded 2 d.p

...read more.

Conclusion

  • I left the power pack on too long. This causes the wire to overheat.
  • When I was measuring the lengths of the Nichrome wire my measurements might have been slightly inaccurate. The rulers used might not have been exact and it was difficult to get an accurate reading of length by eye as the wire was not completely straight. Also the ruler may have been of different thicknesses throughout the length. This would have contributed as a slight error in my results.
  • The ammeter and voltmeter could have been slightly faulty and not given me correct, accurate readings.
  • I connected the wire into the circuit using crocodile clips. These were quite loose and so this could have made my results less accurate. If I improved my method I could either attach the wires with tape but this may affect my results so instead I could solder the Nichrome wire into my circuit.
  • It was difficult to adjust the variable resistor slider accurately only by eye. If I did the investigation again I could try to and adjust the variable resistor accurately I will use an advanced digital variable resistor.
  • I also found it difficult to measure exact lengths against the meter rule because the crocodile clips didn’t clip on to the wire very securely. If I did the investigation again I could pre cut all the lengths of wire before the experiment instead of just connecting the crocodile clips at different distances apart on the meter rule.  

        To further my investigation I could use the same method but increase the range of lengths. I could use lengths of up to 3 meters. I could take readings from lengths at smaller intervals; I could take reading every 5cm instead of every 10cm as I did. I could also take more repeat readings to get a even more accurate average.

...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. An experiment to find the resistivity of nichrome

    ensure a greater accuracy in the obtained results and in the plotted graph. Length of the wire: - At the beginning when I did a preliminary experiment I was using crocodile clips instead of terminal blocks to connect the wire to the circuit.

  2. An Experiment To Find the Resistivity of a Wire

    The results support my predictions well. Doubling the length did double the Resistance as seen in the table above. This wasn't true for all cases as when the wire of length 0.50m with a resistance of 0.74ohms was doubled, the Resistance had an error of 12.8% and did not agree with the other results.

  1. Factors Affecting the Efficiency of a Wind Turbine

    A wind turbine was placed in front of a wind source (Hairdryer). The a/c output was recorded for each length. The windturbine was then equipped with another set of blades of different length. The blades were tested again by using the same technique.

  2. Resistance of a Wire Investigation

    The wire was cut to just over 50cm so the crocodile clips could attach onto the wire, making the results more accurate. Stretch out the wire onto the bench and measure with a metre rule. The power supply was put on 2V and the gradually increased the 4V, to find a suitable current for my main method.

  1. Investigate the resistance of different wires and how at different lengths the voltage increases ...

    which is:- R=V/I An example of me using this formula is below:- Voltage (V) =0.4 Amps (I) =0.3 R=V/I R=0.4/0.3 R=1.33 Conclusions drawn from processed evidence The results given from the line graphs clearly indicate how the length of the wire compares to the resistance, although there were a few

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

    Inversely proportional to its area of cross-section. In other words, its resistance = constant x length Area of cross-section The constant depends on the type of material and is referred to as the resistivity of the material. The unit of resistivity is the ohm metre (?m). the symbol for resistivity is the Greek letter p, pronounced 'rho'.

  1. The resistance of wire.

    essaybank.co.uk This tells me that the voltage measures the amount of energy used up in getting each coulomb of charge through the wire. The units of volts are the same as joules per coulomb. Therefore, Ohms law says the more resistance means more energy used to pass through the wire.

  2. Investigating how the length of a Wire affects its resistance.

    Although most of the points fit quite well into the line of best fit, it becomes obvious that as the resistance and length goes up, the point are further and further off the line of best fit. This can be argued to be because of many reasons.

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