Lab # 5
Group Members: ___________________________________
Ohm’s Law
using a PhET Simulation
The fundamental relationship among the three important electrical quantities
current
,
voltage
, and
resistance
was discovered by Georg Simon Ohm. The relationship and the unit of electrical
resistance were both named for him to commemorate this contribution to physics. One statement of
Ohm’s law is that the current through a resistor is proportional to the voltage across the resistor and
inversely proportional to the resistance. In this experiment you will see if Ohm’s law is applicable
by generating experimental data using a PhET Simulation:
Current and voltage can be difficult to understand, because they cannot be observed directly. To
clarify these terms, some people make the comparison between electrical circuits and water flowing
in pipes. Here is a chart of the three electrical units we will study in this experiment.
Electrical Quantity
Description
Unit
Water Analogy
Voltage or Potential
Difference
A measure of the Energy
difference per unit charge
between two points in a
circuit.
Volt (V)
Water Pressure
Current
A measure of the flow of
charge in a circuit.
Ampere (A)
Amount of water
flowing
Resistance
A measure of how
difficult it is for current to
flow in a circuit.
Ohm (
W
)
A measure of how
difficult it is for water
to flow through a pipe.
Figure 1
Open Source: NSU Physics/PHET Activities
1

Ohm’s Law
OBJECTIVES
Determine the mathematical relationship between current, potential difference, and
resistance in a simple circuit.