SPH3U: Electrical Circuit Concepts
Opening Group Activity: Light Up Your Life
Using only the equipment you have been given (1 light bulb, battery, 2 strips of aluminum foil), devise as
many different ways to light up the bulb as possible. You do not need to use all the equipment. What is
required for the bulb to light up?
What would happen to the bulb brightness if you added another bulb in series with it? What
would happen to the bulb brightness if you added another battery in series with the 1st battery?
A. Group Activity: Water Circuit and Electrical Circuit Analogies
Consider the “water circuit” to the left – a pump
applies pressure on water to force it through a pipe
leading to a tap, through a pool filter, and then back
to the reservoir of water.
Three quantities which relate to the flow of water
through this water circuit are (1) pressure, (2)
resistance to flow, and (3) the rate of flow.
How is the rate of flow related to the pressure
applied by the pump?
How is the rate of flow related to the resistance to
flow?
Now consider the electrical circuit to the left.
Compare the different components of the electrical
circuit to the corresponding components in the
water circuit.
The three most common quantities used with an
electrical circuit are (1) electric potential difference
or voltage (V, measured in volts), (2) resistance (R,
measured in ohms) and (3) current (I, measured in
amperes).
Using the analogy to the water circuit, how is the
current related to the voltage?
How is the current related to the resistance?
B. Group Activity: A Water Park Ride
A water ride at a water park is analogous to an electric circuit. Match the following statements
describing the water park ride to the corresponding electric circuit statements.
Water Park Ride
1. Water flows from a high potential
energy location to a low potential
energy location through pipes.
Electrical Circuit
(a) If there is no complete circuit, there is
no electrical current.
2. If a pipe is broken, there can be no
(b) An electrical current occurs because the
continuous flow of water through the
ride.
3. Energy is required to move the fluid
uphill. A water pump is used to do
work on the water in order to raise it
from a low height (and low pressure)
to a high height (and high pressure).
4. A water pump does not supply water
to the ride – it applies pressure to
water already in the pipes to pump it
uphill.
5. Water flows because of a pressure
difference between 2 locations of
different heights.
electrical potential difference between
the 2 terminals of a battery presses on
electrical charges to move from 2
locations of different electric potential.
(c) Electrical charge flows from high
electrical potential to low electrical
potential through wires.
(d) The battery pumps charge from a
location of low electric potential energy
(the – or negative terminal) to the
location of high electric potential energy
(the + or positive terminal).
(e) Electric charges are already in the wires.
The battery supplies the energy to do
work on the charges in raising them to a
location of higher electric potential.