MY QUESTION IS . . .
Does a long wire have more resistance than a wire that is shorter in length?
In order for it to be a fair I must . . .
Keep certain things the same throughout the experiment. These are: -
The voltage. I will use a power pack and set this at 12 Volts.
The time left on. I will leave it on for 20 seconds and allowing a five-minute cool down time between each length so it is absolutely fair.
A non-coated NICHROME wire with the same thickness and density.
I will repeat the experiment to make sure it was a fair test and then find the average of the two results.
The apparatus I will use . . .
Is listed below along with some of the reason I chose them.
Digital Ammeter: I have chose this rather than using a analogue ammeter because the digital ammeter gives an accurate and precise reading rather than making ends meet and guessing with the analogue.
Power Pack: I have chose a power pack because the energy will never go like a cell. The power pack is connected to the mains and is stepped down to 12Volts.
Digital Voltmeter: Again to get an accurate and precise reading of the voltage.
Rule: To measure the length of the wire.
Stopwatch: To time the length on and the intervals in seconds and minutes.
Hypothesis
When I change the length of the wire I think that the resistance will be more as the wire gets longer and longer. My scientific knowledge tells me that this is because the electrons will have more of a journey to go and thus will bump into each other adding to the resistance because on the way to the next electron they will lose energy.
My predicted graph is shown below. I have complied it on the basis of me thinking that the longer the length the more the resistance.
Circuit diagram
1st set of readings
2nd set of readings
Averages
Conclusion
I have found out that the longer the wire the more resistance that there is. This longer wire adds to the resistance because the electrons have to move along further and thus lose energy.
The pattern that I have discovered is that when the current drops the resistance is higher and when the resistance is low the current is higher.
These results support my Prediction as I said that when the current is low the resistance is high and vice versa. The resistance will be higher in the long wire because of the distance that the electrons have to go.
But I had one result that was out at 20cm. That result must be through the power pack as it is going through the mains at alternating current and this could affect the Voltage
The Line graph below shows the increase of resistance as the length of the wire goes longer. I have drawn a line of best fit.
Evaluation
Below I have made a flow chart to show the step by step ways that I did my experiment and obtained my evidence.
Firstly I started by drawing a circuit diagram to see exactly
how things are going to be set out. What components have
to be in a parallel circuit e.g. The Voltmeter, which measures
the volts going round the circuit. I put this in parallel around the
Nichrome wire.
I then collected all of my apparatus together and set it all up following the circuit diagram. The digital Voltmeter and Ammeter had to be set at a certain point for the experiment I was doing
After all the equipment was connected I turned on the power pack at 12 volts and started the experiment with the Nichrome wire being 5 cm long. I recorded the results that it said on the voltmeter and Ammeter and recorded them both in a table.
As I have I done my experiment twice, it is clear to see that the quality of my results are good as they are all nearly both the same when I did them. But when I went to find the average for some of the results I saw that I had an anomalous results. This was at 20 cm. This result did not fit the trend when I went to draw my graph. This has probably happened at some point where the voltage or timing could be wrong.
My investigation was fair throughout because I stuck with the rules I had set, made sure it was perfect and that I did the timing sufficiently in the whole experiment.
I think the amount of data that I have collected is sufficient enough because it proves my theory and complies with the title. But I could of explored into another factor which could of made the results turn and see which way the resistance would turn from high to low or low to high!
If I was to change anything it would defiantly be the lengths which will be set apart more and longer to give a varied answer.
If I obtained more evidence it would defiantly be more to the part of exploring more factors so that I could see which factors affect the resistance as said in the title.
This extra evidence would make me certain of what factors change the resistance so that the answers would tell me if certain things make resistance go up or down.
