Investigating the Resistance of a Wire
I will be measuring resistance of a wire in two ways. In all
procedures I will use different thickness, length and material of
wire. This should show if the resistance differs due to any of these
variables. Also both experiments will be repeated to try to rule out
any anomalies that might occur. There is only a subtle difference
between the two experiments, and that is that the equipment used to
collect the evidence will be different. For the first experiment I
shall use an ammeter to measure the current through the wire in
current and a voltmeter to find the voltage across the wire. When I
have these figures I can then do the mathematical equation to find the
resistance of the wire. The equation to find the resistance is:
Resistance (in ohms) = Voltage across the resistor* (in Volts)
_______________________________
Current through the resistor* (in Amps)
*In this case the wire that is being tested replaces the resistor in
the equation
Also I will change the temperature of the wire with a Bunsen burner to
see how temperature of the wire has any affect on the resistance .
There will be a set of main components that will be used in both
experiments. Now I will explain how they will be used to give
effective results. The most important part of the equipment is the
system of measuring which is used. A multimeter that measures volts,
amps and ohms as well as other units will be used and will be set to
the appropriate mode to measure the right unit and scale. A voltmeter
will be connected in parallel to the wire so that it can measure the
voltage effectively. The ammeter will be placed in series before the
wire so that it also will measure effectively.
Next is the wire itself. The wire will be measured at different length
so I have chosen to use a scale of 2 – 20cm in length, as I believe
that if the wire is too long or short the results will not be