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

The aim of this investigation is to discover how the length of a wire affects its resistance.

Extracts from this document...

Introduction

Finding the resistance of a wire investigation

Aim

The aim of this investigation is to discover how the length of a wire affects its resistance.

Apparatus

  • Power Pack (AC voltage)
  • Ammeter
  • Voltmeter
  • 100cm of Nichrome wire
  • Crocodile clips
  • Circuit Wires
  • Meter Rule

Firstly, I will briefly explain what voltage, current and resistance is.

Voltage- Voltage is a measure of the amount of "push" given to electric charge in a circuit. We nearly always consider electrons as the charges (charge carriers) being pushed around a circuit. If there is no "push", electrons will not be moved around the circuit. This voltage would normally be supplied by a cell, battery or power pack.

Current- An electric current is the flow of charged particles. Inside a copper wire, current is carried by small negatively charged particles, called electrons. The electrons drift in random directions until a current starts to flow. When this happens, electrons start to move in the same direction, toward the positive terminal. The size of the current depends on the number of electrons passing one place per second.

Resistance-Resistance determines how much current will flow through a component. Resistors are used to control voltage and current levels. Resistance is the atoms of a material getting in the way of electrons, as they travel in the direction of the negative terminal. The electrons collide with the atoms.

Ohms law states that if you have one volt applied to a one-ohm resistance, the current will be one amp.

...read more.

Middle

Hypothesis

1. I predict that as the length of the wire increases, the resistance will also increase in proportion to it. I have come to this conclusion because of my previous studies of resistance, and because of my preliminary results. My logic is that I know that atoms in all conductors have free electrons in the outer shell of their structure. It is because of this structure that the outer electrons can move freely about. I have shown below in the diagram how the electrons move when there is a potential difference passed through a conductive material.

The atoms are arranged in a honeycomb shape.

The free electrons drift around inside the wire, in the general direction of the positive terminal. This is called the electron drift current. As the electrons drift toward the positive terminal, they collide with the metal atoms that make up the wire. These collisions cause the electrons to move more slowly, which in effect causes resistance. If the length of the wire is increased, then the resistance will also increase as the electrons have will have a longer distance to travel, thus more collisions will occur. Due to this, the length increase should be directly proportional to the resistance of the wire.

2. I also predict that as we increase the potential difference in the circuit, the resistance of the wire will increase. I know that current is directly proportional to P.D (potential difference)

...read more.

Conclusion

*The diagram above shows a model of charge moving from a connecting wire to a thinner piece of test wire. The thin wire has less conducting electrons than the same length of connecting wire, and so the charge has to move faster to maintain the same current or flow rate through the thin wire. This should lead to heating of the thin wire, as the electrons transfer their energy in collisions with the metal atoms. The greater the number of collisions, the more energy is transferred as an electron passes through, and the greater the resistance to charge flow.

This is similar to trying to suck milkshake up through a thin straw, or through a thick straw. The milkshake will move more easily up the thick straw, which has a larger diameter. The relationship is one that is "inversely proportional". In other words, there is a direct link between the thickness of the wire, and the loss or resistance, and the larger the area of a cross section of the wire, the lower the resistance.

To keep this experiment fair, I would: use the same connecting wires, submerged the test wire in water, kept the P.D constant, kept the wire material the same and kept the length of the test wire constant.

...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. Marked by a teacher

    Investigating how the length of wire affects its resistance

    3 star(s)

    Evaluation: I generally took enough readings for my graph to give me an obvious trend in the experiment. I felt that after averaging the result from 3 trials, my readings were fairly accurate. Nearly all the points on my graph are fairly close to the trend line, or lying right on it.

  2. Marked by a teacher

    Resistance Aim: my main aim is to investigate the factors that affect the resistance ...

    3 star(s)

    The voltage across each resistors in parallel is the same. The total resistance of a set of resistors in parallel is R = (R1 x R2)/R1 + R2 General Evaluation of Investigation and Improvements The accuracy of my results shows the success of the investigation.

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

    to the current and I could have included a switch in my circuit so that I can break the circuit quickly if I needed to. I made sure that my bag was underneath the table as well so they are not in the way of other people.

  2. Resistance of a Wire Investigation

    These results could be done better. If I were to do this experiment again, I would use newer, more accurate ammeters and voltmeters, a more accurate method of measurement, and take a much wider range of readings, and more readings so that a more accurate average can be taken.

  1. An Investigation into how the Length of the wire affects its resistance

    I am going to use a nichrome wire throughout this investigation because it has a higher density than copper wires. This would be an advantage in this investigation because it will mean that the resistance will be easier to measure.

  2. Investigate how mass affects the diameter of an impact crater.

    Repeat the whole experiment again but stage 3 should be altered so the mass of plasticine is 5g heavier than the one before. This procedure should continue until you have recorded final results for 35g. Safety is not a major factor to take into consideration.

  1. Investigate how the cross section of a wire affects the resistance in a circuit.

    = V I From previous research, it has been discovered that a voltage/current graph for a wire, is a straight line through the origin. This means that the voltage across the wire is proportional to the current through it. Therefore if the voltage would double, the current will double.

  2. An Investigation Into How the Length of a Wire Affects Its Resistance.

    straight * Measure the piece of wire and cut it, using wire cutters, on the 100 centimetre mark * Clip either end of the wire with crocodile clips * Connect the wire in the circuit, as shown in the diagram above * Turn on the power pack at the mains

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