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My results support this as the graph of length against resistance shows that relationship is directly proportional. As the points on the graph are very close to the line of best fit, this supports my prediction. Also as I repeated my experiment 3 times and obtained very similar results, it shows that this experiment is repeatable and reliable. So, I conclude that as the length of wire increases, so does the resistance. I have realised also that double the length means double the atoms, which doubles the collisions and in turn, as explained in my prediction, doubles the resistance.
This leads me also to believe that resistance would be less in smaller wires, this is due to higher current and increased heat. During the investigation three major changes were brought to my attention, these changes were: -> As I increased the length of wire, a. ) The potential difference increased b. ) The flowing current decreased c. ) The resistance in the wire also increased. I also found that when doubling the length of wire the resistance will more or less double also.
E. g. when the length was 50cm the resistance was 4. 00Ohm, and when the length was 100cm theresi e was 8. 00Ohm. Evaluation The experiment I carried out was completed by means of very basic school laboratory equipment. Although reliable and trustworthy evidence was collected, proved by the similar 3 times repeated results and matching line of best fit to my prediction, I believe my results could have been far more accurate with a greater time span and some far more enhanced technical equipment, such as a digital multimeter. Although during my experiment there were no major anomalies there were a few variations within my repeats of the experiment.
These minor variations truthfully had no major effect on the overall experiment due to the diminutive extremity of them. Nevertheless these small variations may have many similar reasons for appearance of which that the major anomaly would have on occurrence. These reasons could consist of such things as: – Loose connectivity and/or faulty equipment – Human error (inaccurate readings and/or checks) – Temperature (collision speed alterations) To improve the accuracy of my experiment It would have been helpful if: – The wire was in a temperature controlled environment, this is because resistance is affected by temperature.
– The voltmeter and ammeter were difficult to take a reading off, this is due to the unsettling of the actual readings, they flicker and change several times before stopping on a final reading. If you move slightly however, the results will flicker again and become distorted. To prevent this, a better quality analogue meter with a built in mirror to prevent parallax could be used to my advantage. – Also, if I had more time I could have extended my experiment and repeated it with shorter intervals of wire.
I could have taken readings every 5cm instead of every 10cm, this way I could gather more information and add a set of supplementary details to my results. If I changed all of the above, in theory I should come across far superior accuracy in my readings. If this theory is correct my results graphs should show a stronger correlation. If I were to present extra evidence I could make the following changes for further experiment. – Increase length of wire – Increase the thickness of the wire, – Change the material of the wire. If the above three changes were investigated for further experiment, I would hope that they would only validate my predictions and basically back up my evidence.