Teaching Electricity
Published on Nov 06, 2015
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Teaching Electricity
Alan Weller UEL, 13/11/17
Starter MIT and light bulb 10 mins.
What are safety issues
5 mins
What do we need to know?
10 mins
What model 20 mins
Plenary Freezeray, Energy echalk. Ball 10 mins
What are safety issues
5 mins
What do we need to know?
10 mins
What model 20 mins
Plenary Freezeray, Energy echalk. Ball 10 mins
Photo by MohammadHasan
Teaching Electricity
- What are the problems of teaching electricity?
- What is a good model for demonstrating electrical circuits and overcoming misconceptions?
- What do we need to know in order to teach electricity effectively?
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STARTER:
Can you light a light bulb with one wire and a battery?
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Safety
- Pupils will want to short circuit components.
- Overheating of components.
- Electrical shock.
- Be prepared for circuits not working, ammeter, voltmeters etc
- What strategies can we have for getting circuits to work?
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Voltage, Potential Difference, EMF
Current, Charge,
Resistance,
Energy, Power
Cell, Battery, Circuit Symbols
What is the difference between an ammeter and a voltmeter? What does a voltmeter measure?
What is energy
What is energy
ENERGY
It is important to realize that in physics today, we have no knowledge of what energy is. We do not have a picture that energy comes in little blobs of a definite amount. It is not that way. However, there are formulas for calculating some numerical quantity and when we add it together it gives “28″—always the same number. It is an abstract thing in that it does not tell us the mechanisms or the reasons for the various formulas. (Feynman)
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MISCONCEPTIONS
Resistors consume charge.
Electrons move quickly (near the speed of light) through a circuit.
Charges slow down as they go through a resistor.
Current is the same thing as voltage.
The bigger the container, the larger the resistance.
A circuit does not have to form a closed loop for current to flow.
Current gets "used up" as it flows through a circuit.
A conductor has no resistance.
The resistance of a parallel combination is larger than the largest resistance.
Current is an excess charge.
Charges that flow in circuit are from the battery.
The bigger the battery, the more voltage.
Power and energy are the same thing.
Batteries create energy out of nothing.
Task
In groups: Using the rope (and post-it notes?) design a demo to model an electric circuit satisfying as many misconceptions as possible.
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Rules: series and parallel
- series: The current is the same the voltages add up.
- parallel: the voltage is the same the current adds up.
