Investigating the Factors that Affect the Resistance of a Wire
To study the factors which affect the resistance of a wire.
Although current and potential difference measure different things,
they are related to each other. In 1826, Georg Ohm discovered that
doubling the p.d. doubled the current. (Taken from
Ohm's Law: the current flowing through a metal wire is proportional to
the potential difference across it (providing the temperature is
Electricity flows through a conductor, in this case the wire, by means
of free electrons. The number of free electrons varies depending on
the material and ...view middle of the document...
During the preliminary work, I tested the method that I would use for
the main experiment to see if it worked and decided to follow it up.
In the main experiment I decided to test two different types of wire
and see which had a higher resistivity.
DEPENDENT - the resistance
INDEPENDENT - the length
CONTROL - the power-pack setting
I think the longer the wire, the more resistance there will be. This
is because the longer the wire, the more atoms there will be for the
electrons to collide with. Therefore the longer the wire, the hotter
it will get when a current flows through it as there will be more
atoms and electrons colliding.
If the length is doubled, I think the resistance will also double
because doubling the wire will double the number of electrons. More
collisions will happen causing a higher resistance.
100cm of constanton wire (SWG 26)
100cm of nichrome wire (SWG 26)
1. Set up equipment as shown in the diagram.
2. Connect one of the crocodile clips to 0cm and the other to 10cm.
3. Record the readings of the ammeter and voltmeter.
4. Move the clip on 10cm up another 10cm and record the readings
5. Continue moving the clip up 10cm and recording the readings until
you reach one metre.
6. Repeat 2 more times so you can work out an average result.
7. Repeat the whole thing with whichever wire you did not use the
Average results for the constanton wire: