- As temperature increases, the resistance in the wire increases.
Length of Wire
When the wire is longer, there are more atoms making up the wire, so it is harder for the electrons to get past them. This makes the resistance larger in a longer piece of wire
The Thickness of Wire
It is easier for electrons to get through a thick piece of wire rather than a thin wire because there is more space and different routes that electrons can take to get to the other pole.
Material of the Wire
Electrons can flow more easily through some material more than others. These are called conductors. A good conductor such as copper is used in telephone lines to deliver internet and voice calls. Those materials that don’t allow electrons through easily are called resistors.
Temperature of Wire
As the electrons travel through the wire they give energy to the atoms of the wire, this makes the atoms of the wire move around more and vibrate more causing the temperature to rise, increasing resistance. When the atoms move around they make it harder for the electrons to get through, this is called resistance.
Prediction
We’re going to investigate the effects of resistance in a circuit. I think that the longer and the thinner the wire is, the amount of resistance will increase because it is harder for the electrons to pass through the longer and thinner wire as there are less routes for it to take. In the investigation we will be using a…
- Battery
- Ammeter
- Voltmeter
- Exposed 100cm wire
We will investigate the voltage on the power pack, the voltage on the voltmeter and the current which will determine a resistance. To make it a fair test, we will repeat the tests 4 times and then determine an average, making the tests fair, and also making the results more accurate. We’ll use different lengths and voltages to put the circuit through its paces to measure the circuit’s resistance.
Observations
I observed that the longer the wire, the more resistance there was because it was more difficult for the electrons to pass through the wire due to amount of routes that the electrons could pass through. Also I observed that voltage on the voltmeter was always about 2 volts less than when it left the power pack.
Circuit
Method
To start with, assemble the circuit as seen above, and then set the power supply switch (shown as a cell on the diagram) to 4V on the power pack, this should make the voltmeter read approximately between 2V and 6V. Then clip the crocodile clips onto the wire 100cm apart then record your results. Then repeat this procedure using difference lengths (10cm each time). However, don’t go below 50cm. Then when you have a set of results, repeat the tests 4 times and work out an average.
Analysis
By looking at my results, I can see that ht e levels of resistance go up according to the length of the wire. However, on the graph there’s a few points that don’t fall into line, this maybe caused by the wire being hotter than usual when we tested them.
My thoughts on the current-length relation are, “as you extend the length, the current slowly decreases” because the electrons have further to go have less space to do it in. This is resistance and this is explains why the current ‘slowly decreases’. This also applies for the amount of resistance once you lengthen your wire
Evaluation
I think our testing was fair due to the number of times we repeated the experiment. The only problems we encountered where that of the circuit temperature when we where testing which would of made an impact on our results. In a perfect world we would have had a circuit for each test to complete eliminate the effects of temperature.
I’d implement the change of more than one testing circuit to my method if I could change it. This with a combination of more test repetition would ensure extremely accurate results. If I had more time to look at resistance, I’d properly look at the effects resistance has over distance in circuits, to get a further idea about the effects of resistance on circuits
