Prediction
I predict that the longer the length of wire I will be using the more resistance there will be, I think this is because the current flowing will have further to travel. Also when a metal wire is placed in an electric circuit, the voltage from the power supply makes the electrons flow through the wire, as they do so they will collide with the metal ions and this process will slow down the flow, so the longer the length of wire the more nichrome atoms there will be for the electrons to pass through. Resistance is how easily electrons can pass through a resistor, a low resistance means that the electrons can pass through more easily.
Preliminary work to back up my plan (from physics.com)
Temperature effects
“If a metal is heated, the metal ions will vibrate more. This means that there is a greater chance of an electron bumping into a metal ion and so the flow of electrons is reduced. I.e. the resistance is increased. An analogy is to imagine that you (the electron) are walking through a crowd of people (the metal ions). If the people are standing still, like the soldiers, you can easily move through by walking along the lines between the soldiers. However if you try to cross a crowded dance floor where people are moving around in all directions, you are much more likely to bump into someone so your overall speed is reduced.”
Obtaining information
During the experiment I collected three sets of results so that an average can be worked out for a single more accurate set. Each set of results contains length (CM), voltage and current (I), with these I can then work out the resistance for each length. I used 2 different types of ammeters one with numbers going up in single units and one going up in decimals to get accurate and precise results.
Resistance = voltage/current
Here are my results after I worked out the average
This table is the average of the three sets of results.
Analysing information
I have noticed a straight line trend from this experiment, it is a straight line because when the wire is cut in half so will the resistance, and when the wire is cut into a quarter so will the resistance I think that this is because the number of metal ions that the electrons have to pass through will be cut, so the electrons will have less ions to pass through, e.g. if the piece of wire has 2 million ions and a single electron tries to pass through it the odds will be, 2 million to 1, but if the wire was cut in half there would be 1 million ions and the odds of the electron getting through would now be, 1million to 1, the odds are halved, and with the evidence of my graph I conclude that the longer the wire the greater the resistance,
My conclusion has supported my prediction 100%.
Evaluating information
Everything went as I suspected even the odd result that I obtained at 10cm of wire, I think the odd result was because 10cm of wire was to short so it started to heat up causing the metal ions to vibrate making it harder for the electron to pass through. But the other thing is that the experiment only goes up to 90cm this was because I needed to tape the wire on the ruler so this took up space, it was due to the planning it is something that could have been improved, but knowing what I know now a simple way to work out 100cm is to take the resistance at 50cm and multiply it by 2. To make this experiments analysis better I could have used different wire to prove my theory correct.
