Voltmeter and another from the volt meter to the crocodile clip.
*You should now have a constant reading from both the voltmeter and
the ammeter for the 10cm copper wire.
*Collect these readings and put them into a table.
*Do this three times for each size of copper wire to make it a fair test.
*Repeat this test but change the length of copper wire by 10cm each time
until you reach one meter.
*To work out the resistance for each size of copper wire, use the equation
Resistance = voltage (pd) / Current (amps)
In 1826, George Ohm discovered that; the current flowing through a metal wire is proportional to the potential difference across it.
(Providing the temperature remains constant)
Fair Test
To make my experiment a fair test, I collected the results for the experiment three times, only changing one variable. By doing this, I will end up with more accurate results.
Safety
- Do not drink or eat in the experiment area.
- Be careful with the copper wire because it may be hot and could burn you.
Prediction
I predict that as the length of the wire increases, the resistance of the wire will increase also and the amps will become lower. Thin wire tends to resist the movement of electrons in it. We say that the wire has a certain resistance to the current. The greater the resistance, the more voltage is needed to push a current through a wire. The resistance in a wire is calculated by:
Resistance = p.d across the wire
Current through the wire
Analysis
From this investigation I found out that as I increase the length of copper wire, the resistance also increases. Thin wire tends to resist the movement of electrons in it. We say that the wire has a certain resistance to the current. The greater the resistance, the more voltage is needed to push a current through a wire.
From my results, I can see that my prediction was correct because as I increased the length of the copper wire, the resistance also increased. In 1826, George Ohm discovered that; the current flowing through a metal wire is proportional to the potential difference across it. (Providing the temperature remains constant).
There may have been other ways that I could of produced results other then line graphs but I thought that line graphs would have been more accurate for this type of experiment.
Evaluation
After doing this experiment, I now understand how resistance in a wire can affect the electrons in it and how more voltage is needed to push the current through the wire.
I think that test two and three had acceptable results but test one had unusual results compared to them. The reason for this may be that we used too many flying leads, resulting in an increase of resistance or the piece of wire may not have been connected properly. The room temperature may also have been a cause of this.
I believe that the method I produced is appropriate for this experiment because it gave me accurate results.
I could improve this experiment if I had more accurate equipment which would improve my results greatly.
A relevant experiment that would work well with the one I have just done would be to test if other types of metal wire that also conduct, affect the resistance in them.
