As you can see from the table the results of the experiment were close to my prediction in that when the voltage stayed the same the current changed as the resistance changed also. Also, the current changed when the voltage changed.
To help to see these results more clearly I have made the graph overleaf with lines of best fit to show the results.
As you can see from the graph there is a relation with each line; all current values increase in proportion to the voltage increase and also the current values get smaller when a higher resistance (ohm) value of resistor is used.
The gradients of the lines on the graph show a relation between the different values of resistors. This is that the steeper the gradient the lower the resistance of the component.
From the graph and table of results I have been able to form an equation to show the relation between Voltage, Current and Resistance.
RESISTANCE = VOLTAGE
CURRENT
Evaluation
For this experiment I decided to use results from 10 groups doing the same experiment to improve the accuracy of my results. By having 10 sets of results I had the choice to disregard any anomalous results. This means that I still have the choice of using my other results but with improved accuracy for an average.
I found the average of my results by adding up each result from each group and then dividing the total by 10, unless there were anomalous results for that resistor or voltage, where I divided by 1 less for each anomalous result disregarded.
In my table of results there were mainly 2 groups who had incorrect values. However I didn’t disregard these as their only mistake was that they had not taken into account the unit needed was milliamps and not amps so when calculating averages I multiplied these results by 10 to make them useable. Also, there were other results in the table which were either far too low or too high to be accurate, therefore I disregarded these results when calculating the averages. These incorrect results could have been due to a battery which was very old and needed replacing or possibly a mistake when reading off the value from the ammeter. There were few results which had to be disregarded when calculating averages as I allowed a leeway of 10% to account for a possible 10% difference in resistance values for the resistor. However this still shows that my results were overall very accurate and therefore reliable. The reliability of these results is also shown by the graph due the points on the graph being very close to the line of best fit.
If I were to do this experiment again then I would try to make my results more accurate and reliable by doing the following;
Using the exact same model resistor to ensure reliability for their values,
Using new same model batteries to ensure accuracy of their values,
Also by using a digital ammeter to ensure no problems of reading off the meter which could cause results to be less reliable.
