Design and Use of Circuits to Explore the Variation of Resistance

Design of Circuits

When designing a circuit to explore resistance, you must tailor your circuit to measure the current flowing through and the potential difference across the component.
A simple series circuit is often used in these investigations. It usually includes a power source (such as a battery), an ammeter, a voltmeter, and the component being tested.

To study how resistance varies with factors such as length or thickness of a wire, the circuit can be repeatedly redesigned with modifications (like changing the length of the wire).
Length: As a rule of thumb, if the length of the wire increases while everything else remains the same, the resistance of the wire also increases.
Thickness: On the contrary, if the thickness but not the length of a wire increases, its resistance typically decreases.

Record the values of current and voltage for each variant of the experiment for comparison.
By calculating the ratio of voltage to current (V/I), you’ll get the resistance of the component for each variant of the experiment – this can be useful in interpreting your results.
Graphical representation of your results might aid in visualizing the variation of resistance with respect to length or thickness of the wire.

Always turn the power off when changing components in the circuit to avoid electrical shocks.
Do not use components with cracks, frayed cords, or damaged insulation.
Check the circuit is wired correctly before turning the power on. Insert fuses or circuit breakers if necessary to prevent overloading.

Note that other factors such as temperature, material of the wire, and type of power supply (AC or DC) could also impact the resistance in a circuit.
Repetitions of each variation and taking an average might be beneficial to reduce the impact of outliers or erroneous measurements.