Overall, my results are very consistent with my predictions. Most of the data points were on, or very close to, the line of best fit. There are a few data points that are farther away from the line of best fit than the others, but they are still consistent with the general trend. There are no anomalous results that I would consider to be far away from the line of best fit.
There are possible sources of error that might have led to inconsistent results, such as a kink in the wire. This would have prevented the area of the wire from remaining constant and would have affected my results. However, I made sure that the wire remained straight throughout the experiment.
I think that the range of my results was sufficient enough for me to draw a valid conclusion about how the length of the wire affected the resistance. This was because I could plot a graph and show the general trend.
I think that the pattern/general trend would continue beyond the range of values I used. However, I think that unless I had specialist equipment the results would be distorted because the wire would eventually get very hot. Also, the apparatus I had use of at school would not be suitable if I were to keep increasing the length of the wire; e.g., in a classroom environment I could not increase the length to more than 150cm because of safety concerns as well as space constraints.
I think my method could have been improved to produce results that were even more consistent. I could have considered using a new piece of wire each time in order to regulate the temperature more stringently. Using the same piece of wire throughout the experiment meant its temperature rose slightly over time, which may have affected my results. However, using new pieces of wire each time would have been too impractical and time-consuming in the context of this lesson. Overall, I think my method was sufficient to obtain reliable results.
To support my prediction and conclusion, I could do further experiments. For example, I could use different types of wire instead of using only nichrome. I could also consider using different cross-sectional areas of wires or even change the temperature of the wires deliberately and see how manipulating these variables affect the resistance of the wire.
Factors Affecting The Resistance Of A Wire
Factors affecting the resistance of a wire
Resistance is a force, which opposes the flow of an electric current around a circuit.
Resistance is measured in Ohms. George Ohm discovered that a circuit sometimes resists the flow of electricity. He called this 'RESISTANCE.' He even came up with a rule for working out the resistance of a circuit, which was:
R= V ÷ I
Ohms law says the more resistance means more energy is needed for the current to pass through the wire. Resistance is a measure of how much energy is needed to push the current through something.
Resistance occurs when the electrons travelling along the wire collide with the atoms of the wire. These collisions slow down the flow of electrons causing resistance.
THE FOUR FACTORS THAT AFFECT THE RESISTNCE OF A WIRE ARE:
1. LENGTH OF WIRE
2. THICKNESS OF WIRE
4. TYPE OF METAL
To investigate how the length of a Nichrome wire can affect the resistance of a wire
In my opinion the longer the wire the more resistance there will be. I believe this because if the length of the wire is increased then the resistance will also increase, as the electrons will have a longer distance to travel and so more collision and friction will occur.
The factors that I am going to vary are the length of the Nichrome wire and adjust the variable resistor to take 3 readings.
The factors that I am going to keep constant are: same thickness of the wire and the set up of the circuit should be the same.
v NICHROME WIRE
v POWER PACK
v METER RULER
v CROCODILE CLIPS
v CONNECTION LEADS
v VARIABLE RESISTOR
I started of with the experiment by setting up the circuit as shown above. I had to be careful in connecting the circuit, because the voltmeter had to be placed in parallel and the ammeter, which had to be placed in series. The Nichrome wire was cut to just over 100cm so the crocodile clips could attach onto the wire, making the results more accurate. I stretched out the wire and sellotaped it to the ruler. I did this so I do not need to cut the wire every time; all I have to do is just move one of the crocodile clips to another length. The power supply is then switched on and put on 8 volts. I will then record the reading of the ammeter and put the results in a table. After this I will adjust the variable resistor to 7 volts, which would show up on the voltmeter, I will record the reading of the ammeter. I will once again adjust the variable resistor to 6 volts this time and record the reading.
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