Length of wire

Method:

1. Check that the ammeter and the voltmeter are working properly by creating a simple circuit.
2. Set up the apparatus as shown in the diagram connecting each of the apparatus using the croc clips.
3. Switch on the power pack at 2 volts.
4. Conduct 2 tests for each thickness of wire (on the ruler) and record down their voltage and current for each one.
5. Collect the result of the voltmeter and the results of the ammeter in a table.
6. Test the different thicknesses (conduct 2 tests for each wire thickness) of wire and collect their results of the ammeter and the voltmeter on a table as well.

Notes:

1. For the voltmeter the wire should be at point 0 and 5 and you have to read from the bottom scale.
2. For the ammeter the wire should be at point 0 and 1 and you have to read from the top scale.

Safety:

1. Be careful not to touch any of the apparatus, especially the wires when the power pack is turned on as you might electrocute yourself.

Variables Table:

Measurements: There are only 2 measurements that need to be measured during this experiment and they are the measurements of the current and the voltage.

Fair Test: To make it a fair test, every measurement taken should be done accurately. I am going to keep the voltage produced by the power pack the same because to test the effect of length of wire on resistance, the initial voltage will have to be the same to make it a fair test. I will also use the same voltmeter to make sure that the results come out with a pattern as other voltmeters may show a higher reading compared to the voltmeter I am using for this experiment. The same goes for the ammeter. I will also keep the variable resistor the same because other variable resistors might be more powerful or weaker compared to the variable resistor I am using for this experiment. That will also maintain a fair test. The length of the wire should also stay the same because that is one of the factors affecting the resistance. The material of the wire should also be kept the same throughout the experiment because different materials have different ionic structure. We will also keep the temperature the same as it is one of the factors affecting the resistance. We can keep the temperature the same by not switching on the power plug for a long time and by taking the measurement as quickly as possible as keeping the power plug on for longer time produces heat changing the temperature.

Results Table:

Interval: I have used a regular interval because we need to have consistency throughout the experiment to be able to draw a graph. The reason why I have chosen 2 is because there cannot be a lot of increase in the thickness as it is not possible to get wires that are extremely thick in length.

Range: I have chosen 8 as the range because it is difficult to find wires that are extremely thick or extremely thin so it is best to stick to a small range than to buy wires for this experiment. Moreover, 8 is an adequate range to investigate the trend in this experiment.    

Conclusion: By looking at the graph and the line of best fit, I can conclude that as the thickness of the wire increases, the resistance decreases. By looking at the graph, I can also tell that if the thickness is 22, the resistance is 9.25. If the thickness is 24, the resistance is 11.38(and the graph curve goes on).  

Link Statement: The apparatus and the methods in this experiment stay the same. We will be keeping the voltage and the current the same. The only thing that we will be changing is the thickness of the wire. Now, that found an effect on resistance by changing the thickness, we will keep the thickness the same in the main experiment. This will help me in the main experiment to make sure to keep the thickness the same to analyze the effect of length of wire on resistance.