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.
What Factors Affect The Resistance Of A Piece Of Wire(Evaluation Missing)
The aim of this is to investigate how the length of a wire affects the resistance of it.
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 have 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.
In this investigation a simple circuit will be set up to read the voltage and current when the length of the wire changes. The length will range from 10cm - 100cm (1m) with intervals of 10cm. The length of the wire will be changed by moving the crocodile clip across the wire on a ruler. We decided that the best thickness of wire to use would be 30swg.This is because a thicker wire would cause too much heat, and the resistance of a thinner wire would be high and difficult to measure. The reason for this is that a thicker wire has less resistance, because there is more room for the electrons to travel through it.
We did preliminary tests to ensure that the wire did not get too hot, and how many cells to use in the circuit. The number of cells I used was important, as it would determine how hot the wire got. If the wire got too hot, energy would be given off as heat, and the resistance would be increased. We did a test that used the same piece of wire at different lengths with 1 and 2 cells. The results showed that with 2 cells, the resistance was higher due to the wire being hotter. For this reason I will use 1 cell to keep it a fair test.
The circuit should be set up as in the circuit diagram. It is important that the voltmeter is set up in parallel and the ammeter in series. The readings from the ammeter and voltmeter will be used to work out the resistance. This can be done using the formula:
V = IR
Where V=voltage, I=current and R=resistance. This can be rearranged into:
This meant that I could find and record the...
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