N.B: My results in these experiments are shared with my classmate, John Morgan, as we worked together on this investigation.IntroductionThis experiment has been set up in order to find the resistance of a nickel chrome wire when a current is passed through a series circuit. The resistance is calculated by using Ohm’s law of:Resistance = Current / VoltageWe will also connect a voltmeter in a parallel format across the nickel chrome wire, which will tell me the reading across the nickel chrome wire, rather than if it was included in series with the rest of circuit, it would give us the reading of the whole circuit, rather than what we need: the voltage of the nickel chrome wire.
VariablesIn this experiment, my input variables are:1. The length in which we measure the current and voltage at (to then calculate the resistance using Ohm’s law)My output variables are:1. Current2.
VoltagePredictionIn this experiment, I predict that the shorter distance across the nickel chrome wire I measure will mean the higher a current reading will be measured. I think this will happen because as a current passes through a wire, the wire heats up – thus building up resistance, and over a longer length of nickel chrome wire, more current will pass through, thus giving more resistance because the current has further to travel. I also think that over a longer distance of nickel chrome wire, there will be less voltage passing through, because there is a longer distance to travel, thus losing voltage.Experiment steps1. Collect apparatus and set-up up the circuit as seen bellow under “Plan”2. Collect data as seen in Results3. Plot graphs for data4. Find correlation and line of best fit5.
Analyse investigation, results and improvements if this experiment is repeatedWhile collecting the results of this experiment, I have recorded the results in a Microsoft Excel spreadsheet, which has also allowed to me work out other calculations within the data.Apparatus1. Wires – used to connect the circuits2.
Voltmeter – to measure to voltage (0.01V to 0.99V)3. Ammeter – to measure the current (0.01A to 0.99A)4. 1 meter of nickel chrome wire – to test current and voltage over5. 12 volt battery – to power the circuit6.
1 meter rules – to measure the distance measuring7. Crocodile clips – to connect the circuit together (wires etc)PlanThe series circuit looks like so:Notice how the Voltmeter is in parallel across the nickel chrome wire to allow us to only get the voltage across nickel chrome wire, rather than in with the series circuit, which would have given us the voltage of the whole circuit.Risk AssessmentThe risk factor in this experiment is very high. One risk that could occur is the fact that the nickel chrome wire can get very hot. If touched while conducting this experiment or any other experiments, blistering hot metal can cause severe burns If you do conduct this experiment and do get burnt, always consult a doctor or someone of similar profession. To avoid this, always keep things away from the nickel chrome wire, and always ensure that you are as quick as possible while measuring the voltage and current of the nickel chrome wire, to ensure minimisation of time to get injured.
ResultsThese results were worked out in Microsoft Excel, to provide 100% accuracy. We repeated the experiment 5 times, to get more accurate results. Bellow are the results for each set.AveragesGraphs/data representationThe next page is the graphs that represent the average Resistance data collected, representing the table above.ConclusionTo conclude, I think to my results safely show that my prediction was correct. After finding the results of the experiments and looking at correlation, it clearly shows that the longer the distance measured the higher the resistance.
To find the scientific reason for the slight curve in some of my graphs, I decided to look through several Physics books, including Physics 4 You. This book told me why the graphs look as the do, which also proved my theory correct. My graph doesn’t show any signs of miscellaneous data, however if I had have repeated this experiment multiple time over using the same battery, until the battery became low on charge, I think that some miscellaneous data might occur because the battery would have to “force” out energy which wouldn’t follow a particular pattern.EvaluationDespite this, I do however believe that the results didn’t show a very accurate presentation of resistance over a nickel chrome wire, to improve these results, I think that I could have done any of the following things:* Made more repetitions of this experiment* Measured the distance over a longer distance, to see if a bigger curve appears in the graph, thus giving bigger correlation..
. Could have an effect on the results of the experiment. My graph clearly shows some correlation and a slight curve. This curve shows that the resistance increases because the wire begins to heat up, and increases in resistance so less current can pass through.