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Instructor Outline: Circuits
UM Physics Demo Lab 07/2013
Lab length: 70 minutes
Lab objective: Instruct the students about a complete circuit, continuous paths for
the flow of current, measuring current and voltage to calculate power, preliminary
series and parallel.
Materials
1 battery
1 flashlight bulb
1 strip aluminum
1 green multimeter (with leads)
1 battery board
1 alligator lead card
Exploration stage: 15 minutes – Group Lab-Work
***Note: the students may short out the battery causing heat and discomfort. This isn’t
hazardous; you can warn them at your discretion.
The students build a basic flashlight with three ingredients (a battery, a bulb, and
an aluminum strip). They see how a complete circuit works. The students then build a
more complex circuit with a switch on the battery board.
Analysis stage: 10 minutes – Lecture
The instructor analyzes the findings in the exploration stage, and answers
questions formed during that stage. Concept development is done on circuits,
flashlights, and the pre-lab question about complete paths for electrons to travel. The
concept of a schematic is introduced. Power, and how to measure current and voltage
are also introduced. The students can use the analysis text to follow during the lecture,
read it at a later time, or use it as a reference only.
Activity: Current travels quickly, but individual electrons do not. One group example of
this is for everyone in the class stand in a circle and passes a gesture around the circle.
The gesture can travel faster than individuals can move.
Application stage: 40 minutes – Group Lab-Work
The students measure voltage and current to calculate power. They build
different types of circuits including series and parallel to observe electron paths. They
also build other types of circuits to explore using the lab materials.
Summary: 5 minutes – Lecture
This is a final opportunity for questions to be addressed. This is time to formalize
the series and parallel observations that were just made. Christmas tree light technology
is a good example of this.
Concepts developed:
1. Electrons require a complete circuit to travel.
2. Power is energy per unit time, measured in Joules/second = Watts
3. Power in a circuit is the product of voltage and current.
4. Introduction to series and parallel circuits.
5. Proper connection to the mulitmeter for current and voltage measurements.
6. The multimeter is configured to describe conventional current which flows from
the positive terminal of the battery to the negative. The electrons are actually
flowing from negative to positive.
Suggested Demonstrations:
Flashlight (can be taken apart during analysis to show simple components)
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