An experiment to investigate the factors affecting the electrical resistance of a wire All wires in a circuit offer some resistance to the flow of charge. Wires with a low resistance allow electrons pass through easily, however, wires with a high resistance need more collision to move the electrons through them. By altering the resistance of a circuit, we are also changing the currents and voltages. Aim In this experiment, I am going to investigate how would the length affects the electrical resistance of a wire. Plan and fair-testing.
Circuit diagram of set up: Apparatus: 1. Voltmeter 2. Ammeter 3. Variable resistor 4. Battery 5. Wire 6. Wires for connections of the circuit 7. Crocodile clip By using the above circuit and the apparatus, I can then able to start my investigation. For this experiment, I am going to use 8 different lengths of wire and they will be from the range of 10 cm to 80 cm. This can provide me a more accurate and reliable results. First of all, I should start with a wire of 80 cm long as the wire, then hold it with a crocodile clip in order to stable it.
An ammeter and a voltmeter is linked to the circuit and therefore, when current flow through the circuit, I will be able to read both the results on the ammeter and voltmeter. To obtain more than 1 set of readings, I will change the resistance on the circuit by altering the variable resistor. This can provide me a different voltage and ampere as the amount of current passes through the circuit has varied. After I have got eight sets of different readings, I can then start the experiment with other different lengths and continue until I have got all eight different lengths done.
It is essential that to keep the thickness and the material of the wire the same throughout the experiment because by using different piece of wire, it will affect the reliability of the results. As a result, I will use a same wire and starts investigate with 80 cm and then cut off 10 cm each time and continue until the last set of result. Fair test To ensure this is a fair test, I have to keep all the factors that would affect my result constant throughout the project. These are the factors that will affect the resistibility of the circuit: 1.
The diameter and the thickness of the wire 2. Temperature 3. The material of my wire To reassure the diameter and the thickness of the wire is the same, I have to use the same wire, which is the wire for the entire experiment. Besides, the apparatus that I begin with should be kept the same to avoid a tiny little difference of the resistance. Temperature is also a crucial factor that should be kept constant. However, it is very hard to maintain the same temperature for each test so I will wait for a minute after I have finish one set of readings in order to cool down the wire.
Hopefully this can provide some time for the wire to cool down and remain a similar temperature as the one I do for the first one. Prediction For this investigation, I think if the length of the wire increases, the resistance throughout the circuit will increases as well, as there are more vibrating positive ions in a longer wire which will increase the electron flow. In other word, the distances for the electrons to migrate have increased. The electrons have to move a further distance through the metal.