We did the same experiments again but with Copper wires.
We started with 10 cm long wires, switched the circuit on, read voltage, recorded it and solved out the resistance. Then we did the stages on 15,20,25 and 30 cm long wires, read voltage, recorded it and solved out the resistance. We repeated the three experiments again to take the average of two results.
We started a new experiment and in this experiment the length is constant (15 cm) and we were trying different numbers of thickness (20 swg, 26 swg, 32 swg).
We started the experiment by using Nichrome (15 cm) and 32 swg thickness (thinnest). We put the wire in the circuit and switched the circuit on. We read the voltage, recorded it and solved out the resistance. Then we did these same stages again but with 26 swg thickness wire then 20 swg thickness wire. Read voltage, recorded it and solved out the resistance. We did the same experiment but with Constantan wires and the length is constant (15 cm). We started with 32 swg thickness wire. We put in the circuit, read the voltage. Recorded it and solved out the resistance. Then we repeated that with 26 swg and 20 swg thickness wires. Read voltage, recorded it and solved out the resistance. We did the same experiment again but with copper wires and the length is constant (15 cm). We started with 32 swg thickness wire. Then we read the voltage, recorded it and solved out the resistance. We did the same thing with 26 swg wire and 20 swg wire. Read voltage, recorded it and solved the resistance out. We repeated the whole experiment to take the average of two results. We did and started a new experiment and in this experiment we did small three different experiments. In each experiment the length and the thickness were constant and we used different materials (Nichrome, Constantan, Copper).
Firstly we started the experiment and in this experiment the length is 10 cm and the thickness is 20 swg. We started with Nichrome and put it in the circuit, read voltage, recorded it and solved out the resistance. Then we did the same stages but on constantan wire. Then we did it on copper wire that also has the same length and thickness.
We did the second experiment that we will used in wires of different materials but have length of 20 cm and thickness of 26 swg. We started with Nichrome wire, then we put in the circuit, read the voltage, recorded it and solved out the resistance. We did the same experiment with Constantan wire then Copper wire. We also read the voltage, recorded it and solved out the resistance.
We did the third experiment with wires of 30 cm length and 33 swg thicknesses. We started with Nichrome wire, read the voltage, recorded it and solved out the resistance. Then we did same thing but with Constantan wire then with Copper wire. We did the same thing of reading the voltage, recording it and solving out the resistance.
We repeated the three experiments to take the average of two results.
Results:
Nichrome, 20swg
Constantan, 20swg
Copper, 20swg
Nichrome, 15cm
Constantan, 15cm
Copper, 15cm
Length, 10cm. Thickness, 20swg
Length, 20cm. Thickness, 26swg
Length, 30cm. Thickness, 32swg
Conclusions:
As I predicted, the longer the wire, the greater the resistance, the thicker the wire, the smaller the resistance and a choice of different materials give different resistance, I found by the results that my predictions were right.
In the graphs I did, they all support my predictions. In the first graph (Nichrome, 20swg), the trend showed that when the wire gets longer, the resistance gets greater. Also the second graph (constantan, 20swg), the trend showed the same thing. But the third graph (copper, 20swg) is quite an anomalous graph and I’ll talk about it in my evaluation.
The second experiment’s graphs also supported my second prediction, the thinner the wire, the greater the resistance. As the trend in first graph (Nichrome, 15cm) showed that different thickness give different resistance and increasing of the thickness of a wire decreases its resistance. In the second graph (Constantan, 15cm) the trend also proved that thicker wires have less resistance. Same thing as in the third graph (Copper, 15cm). In the 7th graph (10cm, 20swg) which we used constant length and thickness and different materials. This graph showed that different materials give different resistance and that what I predicted. In the second graph (20cm, 26swg) also supper my prediction. Even the third graph (30cm, 32swg) showed the same thing, and in the three graphs, all trends showed that Nichrome has greater resistance than Constantan and Copper.
In my knowledge of Resistivity and the law of it ( = —— ) then the factors, which effect the resistivity and they, are the resistance and the length and this law support my prediction and results on the graphs. As I said before that longer wire has greater resistance and that what the law supports. Also I said that thicker wire has smaller resistance and thickness depends on the cross section area and the law supports that.
Also the tables for all results have supported my prediction excluding one anomalous table (Copper, 20swg). And what I did is doing each step twice to take then the average of two for instance I put the wire in the circuit, read the voltage record it then do the same thing again to have two results of voltage, two results of resistance and one result of average.
Evaluation:
The reliability of my results was fine because most of my results including tables and graphs were the same of what I predicted and I think the results were sensible and gave a clear vision to have an easy conclusion. Except for that, there was an anomalous results and it was in table and graph 3 (Copper, 20swg) and the first two results on the graph were increasing as it should be, but then the third result went down, also fourth and fifth results and we would have more time then we’d do the experiment again to have fine, right results.
My results have supported my conclusion a lot because the results were clear and easy to sort it out, so it gave me a wide range of conclusion. Also the results were easy to plot them on a graph and that what made the conclusion better.
I think the investigation method and the results can be improved by working the experiment individually because this will give clear method, better results and wide average of results.
In my opinion, if we had more time, then we would each experiment at least three times to have better average. Also if we had time, then we’d do the anomalous result experiment again and have a better sensible result.
There were some thing, which effected the results of the experiments, and one of them is the crocodile clips and we noticed that putting the wire on the edge of the clip gives a different result than putting it far inside the clip. Also we had to clip the wire right exactly on the edge to give proper result. Because of doing the experiment all along 6 days and we didn’t use the same exact equipment each day then this may effect the results. Once, we measured the thickness of one of the wires and we found that it has different thickness than it says on the label and that effects the results, of course. One of the important things, which can effect the results of resistance and that, is Heat. When we used a bulb in the circuit, the filament in the bulb gets hotter and when it gats hotter, the atoms of electricity get collision and move faster and this happens can effect the resistance, therefore the results at beginning of the experiment differ the results at the last of the experiment.
I suggest that to extend the enquiry of the experiment, we shall use much longer wires e.g. 2m, 3m… and by that we can have better sight on resistivity.
