be defined as the movement of electrons. Three of the most important concepts
to understand in order to manipulate electricity to perform work are voltage,
(measured in volts (V)) describes the amount of
potential energy between two points on a circuit and is created by a difference
in charge between those two points.
(measured in Amperes (A)) is the rate at which electrons
flow through a circuit. A rate of one ampere is equivalent to 1 coulomb
standard unit of charge) per second.
(measured in ohms (Ω)) is a measurement of how much a
material resists the passage of current through the material. Materials
with high resistance are referred to as insulators, while materials with low
resistance are referred to as conductors.
Students in a physics course conducted several experiments to investigate the
relationship between these three electrical properties.
Students were provided with a variety of batteries, resistors
(electrical components that resist the flow of current), and an ammeter (a
device to measure current flow), along with wire and connectors. The students
constructed circuits based on the circuit diagram below and measured the
current in each circuit. Table 1 shows their results.
To further study the property of resistance, students replaced the resistor in
their circuit with coils of nickel wire of various lengths. Students used a
variable power supply to adjust voltage until current was equal to 1 A. They
then used the relationship between voltage, current, and resistance determined
in Experiment 1 to calculate the resistance of the wire coil. Their results are
graphed in Figure 2.
Students repeated the procedure from Experiment 2 using 1 meter wire coils of a
variety of other metals. Their results are given in Table 2.