When everything was connected and working, we turned on our power pack and began the experiment. First we drew a table to record our results. My partner recorded the results and I carried out the experiment. I measured the voltage when there was a constant current of 1amp and the wire length was 35cm. We repeated this procedure six times, but each time we made the resistance wire 5cm shorter. The current was kept at 1amp throughout the experiment by adjusting the voltage.
We carried out the same experiment, with all the procedures and materials as above, another two times. So in total, we had three sets of results. We carried out the experiment three times to improve the accuracy of our results and we calculated the mean of the three result.
RESULTS:
1st set of results:
2nd set of results:
3rd set of results:
Averaged Results:
CONCLUSION:
To maintain a constant current of 1amp (i.e. the flow of electricity) we had to decrease the potential difference (voltage) as the length of the wire decreased.
The evidence from the experiment proves that the hypothesis was correct, the longer the wire, the greater the electrical resistance.
The current is the flow of electrons from one end of the wire to the other. The electrons have to pass though the metal lattice and on that journey the electrons hit the metal ions, which is the source of the resistance.
Further Experimentation
We could explore thickness, temperature and the type of material used.
Even if we didn’t explore these factors, I would hypothesis that the thicker the wire, the less resistance there would be, as the electrons have a larger surface area to move through the lattice.
The higher the temperature of the resistance wire, the more resistance there would be, because the electrons would have ions to bump into and cause friction.
If the material used was copper there would be less resistance then using chromium, because copper has less resistance then chromium. Copper has ions which move about less, which allow the electrons to move through the metal lattice without being hit by ions. Chromium on the other hand has metal ion which move a lot, so the electrons have a higher chance to hit the metal ions.
The shorter the wire the smaller the resistance.
