Resistance of a Wire

3. Attach the crocodile clips to wire then measure the length and then readjust it to 10 or your starting point.

4. Draw up a table

5. Collect your results; make sure you have at least 5 results in one test. Do not touch the wire when collecting your results because it will be hot.

6. Do a second test repeating stages 4 and 5.

7. Draw a graph to show your results and write up your experiment.

Fair test

To keep it a fair test I will try to keep all of the above variables the same and I will do the test at least 2 times approx. To see if my prediction was right. I will also keep the same equipment

Preliminary Experiment

I carried out a preliminary experiment to see if there were other factors that could affect the experiment and also to see if I could improve any of the steps in the method. This showed that the wire was very weak if given more than 5 volts because the wire lets electricity flow faster and faster which then leads to the heat eventually breaking the wire.

Results

Test 1

Length voltage current resistance

0 1.9 -1.55 1.2

20 2.1 -0.9 2.4

30 2.2 -0.65 3.4

40 2.3 -0.51 4.6

50 2.4 -0.41 5.8

Test 2

Length voltage current resistance

0 1.92 -1.56 1.2

20 2.14 -0.88 2.4

30 2.24 -0.65 3.4

40 2.35 -0.49 4.8

50 2.42 -0.39 6.2

Evaluation

Procedure

The experiment went very well there were no technical glitches. If I could improve the experiment I would set up the experiment properly and take more accurate results by either measuring it at 15 or 5. These could then reinforce what I am trying to prove scientifically. Also I could redo the experiment using a different voltage.

Accuracy

All the points are close to the line except in test 2 when the point was lower than the line. This suggests to me that something happened then like a misreading etc. I think that if I had more results it would back up the evidence that would reinforce the prediction that I made at the start of my course work. The graph of experiment 1 is a straight line through the origin, which means Resistance, is directly proportional to Length.

Reliability

In both of my graph they follow similar patterns. Both are following straight lines and both have points reasonably close to the line. The results are similar showing that I completed the task with some accuracy. However I could not find any patterns in the results.

Conclusion

I have found out that as the length increases the resistance increases showing that my prediction was right the resistance increased because of the current, which had to pass through more atoms which were bouncing all over the place showing that it was hot, in the wire so there is more resistance for the current. I think that if I have more results my prediction would be that eventually the line would straighten out graphs 1 and 2 have both increased steadily as the length increases and it gets hotter.