Learning strategy for memory: Ohm’s Law and Watt’s Law
This is to address learning two electrical formulas that most secondary students,
post secondary science students and many trades students need to be able to
solve for. Ohm’s Law and Watts’s Law. These two laws are closely associated with
each other and are often confused as to which is which with students. There are a
total of six variables that could be solved for between these two formulas.
Remember that current and electrical pressure are used in both formulas so
remembering these two, will make remembering all the variables slightly easier.
Or slightly harder if you do not remember them.
As a post secondary or trades student you will be applying these two formulas in
your electrical lab. classes. If you could equate how and why electrons flow in an
electrical circuit, with the flow properties of something very familiar, your studies
of these circuits will become more clear.
We are going to use water flow properties as a learning tool. We are all very
familiar with how water flows down a river or through a pipe. We have all used
water flow and pressure to blast away dirt or engage in horseplay.
We will use letter groupings of three and visual images to cue us as to how to use
the letters.
Ohm’s Law This formula lays out the relationship of electron flow in an electrical
circuit to the pressure pushing the electrons and the resistance to the flow of the
electrons .E = I x R. Watt’s Law states that Power is relative to the amount of
electron flow multiplied by the electrical pressure. P = I x E
The one nice thing that both these formulas have is that there is three
components to each formula. Studies indicate that groupings of three is most
effective. While this is a way that we often recite telephone numbers ( two
groups of three then breaking the last four into two groups of 2) I would like to
present the idea that these two formulas are by their structure singular
groupings of three. EIR and PIE.
Next the student can be shown how to make a mental picture of the formulas.
Picture associations make bridging the gap between the concrete state to the symbolic easy.
When the number components of a math fact are pictured as a character, memorization of that
fact is easy.
We can present this in a triangle form:
1
Another way to look at electricity flow in a circuit is to equate it with water flow.
. "According to Zellman, "turning information into a silly picture is an easier and more pleasant
way to study....the more silly or absurd the image the more likely you'll remember or recall it"
For this example we can use two ways to picture water flow. Even three if you
would like to include a water gun fight!
Electrical Circuits and Water Flow.
There are a great visual ways to remember how electrons flow in an electrical
circuit that uses water flow as an example.
One way is to picture a water reservoir.
The water in the reservoir has a pressure that is due to gravity. This pressure is
voltage in electricity. The gate that holds the water back is the resistance in an
electrical circuit. When the gate is opened and water flows out represents the
current flow in the circuit.
As the water level in the reservoir rises the pressure rises. When the level falls the
pressure falls. When the gate opens wider the resistance to water flow decreases
and more water flows out which is an increase in current.
The next image to try is a garden hose.
The hose is the electrical circuit. The tap that the hose is connected to provides
the pressure, E ( voltage), the nozzle provides the resistance to water flow, R
( resistor) and as the nozzle is opened or closed the amount of water flowing
through the hose will increase or decrease, I ( current). EIR
Time for a water fight people! Watt?!!
Get one super soaker
and fill with water. If you want to hit your opponent with the most water power
(P) you need to pump up the super soaker to get the maximum pressure in the
reservoir. (E) pull the trigger and have the most amount of water flow aimed at
your opponent.(I) PIE.
Remember EIR and PIE. Equate EIR with a reservoir or garden hose to explain
Ohm’s Law and PIE with a super soaker to explain Watt”s Law.