Controlling resistance
In this activity, students explore the concept of variable resistance by using a simple electrical circuit.
Making a ‘cracked carbon’ volume control
This experiment uses pencil lead as it contains carbon and carbon is a good conductor of electricity. A 9V battery, two wires and a buzzer (9V) are some of the additonal materials required to help construct the circuit.
By the end of this activity, students should be able to:
construct simple electrical circuits to explore variable resistance
show that the flow of electric charges can be controlled and modified by changing the length of wire or strip of carbon that conducts the current.
Download the Word file (see below) for:
introduction/background notes
what you need and what to do
discussion questions
student worksheet.
Related content
The article Electricity and sensors explains the basics of electric currents, circuits, conductivity and switches. Discover more about the the role of resistors in controlling the flow of electrical currents.
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