Overall, my results are very consistent with my predictions. Most of the data points were on, or very close to, the line of best fit. There are a few data points that are farther away from the line of best fit than the others, but they are still consistent with the general trend. There are no anomalous results that I would consider to be far away from the line of best fit.
There are possible sources of error that might have led to inconsistent results, such as a kink in the wire. This would have prevented the area of the wire from remaining constant and would have affected my results. However, I made sure that the wire remained straight throughout the experiment.
I think that the range of my results was sufficient enough for me to draw a valid conclusion about how the length of the wire affected the resistance. This was because I could plot a graph and show the general trend.
I think that the pattern/general trend would continue beyond the range of values I used. However, I think that unless I had specialist equipment the results would be distorted because the wire would eventually get very hot. Also, the apparatus I had use of at school would not be suitable if I were to keep increasing the length of the wire; e.g., in a classroom environment I could not increase the length to more than 150cm because of safety concerns as well as space constraints.
I think my method could have been improved to produce results that were even more consistent. I could have considered using a new piece of wire each time in order to regulate the temperature more stringently. Using the same piece of wire throughout the experiment meant its temperature rose slightly over time, which may have affected my results. However, using new pieces of wire each time would have been too impractical and time-consuming in the context of this lesson. Overall, I think my method was sufficient to obtain reliable results.
To support my prediction and conclusion, I could do further experiments. For example, I could use different types of wire instead of using only nichrome. I could also consider using different cross-sectional areas of wires or even change the temperature of the wires deliberately and see how manipulating these variables affect the resistance of the wire.
Resistance Of Wire Investigation (Length) Essay
In this investigation I am going to investigate how the length of a piece of wire affects its resistance. The following are all variables that affect the resistance of the wire:
- The thickness of the wire is a big variable as the thinner the wire the bigger the resistance. This is because the current has to squeeze through a thin wire, but it can easily flow through a thicker one.
- The length of the wire is also a big variable as the longer the wire the more atoms the electrons will hit making it a bigger resistance.
- The temperature of the wire effects the resistance because as it gets hotter the atoms inside it vibrate more which increases the chance of the electrons hitting them so the hotter it gets the more resistance it has.
- The type of wire can also affect the resistance because different metals have different amounts of free electrons and the more the smaller the resistance is.
These variables will all effect my investigation but I am going to use the length of the wire as the variable and keep the others the same to make it a fare test.
I predict that the longer the piece of wire, the greater the resistance will be. This is due to the idea of the free moving electrons being resisted by the atoms in the wire. In a longer piece of wire, there would be more atoms for the electrons to collide with and so the resistance would be greater. The relationship between the wire length and the resistance should be directly proportional. This is because in a wire twice the length of another wire there would be double the amount of atoms causing the resistance.
An example of this would be in a 20cm wire. The electrons would have to travel double to distance if it has to go through a 10cm wire. This would in turn double the amount of atoms that the electrons would collide with and then resistance would double.
I will need the following apparatus; a meter ruler with wire taped on it, a voltmeter, an ammeter, some wires, a power pack and two crocodile clips.
In this investigation I will measure the resistance of the voltage and the amps so that I can times them together to get the resistance. I will do this at 20 centimetre intervals. To make it a fair test I will do one at least three times and find the averages. The only variable in the test will be the length of the wire. The wire must be pulled tight against the ruler and taped in place to ensure the length is accurately measured. The same circuit must be used throughout.
Firstly I will set up my apparatus as shown in the diagram above. Then I will measure the voltage and the amps at 20 cm intervals. I will only have the wire connected in the circuit for a few seconds so that it does not heat up and effect the results. I will then repeat each one three times make an average. I will record these...
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