Electric Circuits Notes

Engagement Learning Objectives

• By the end of the lesson, students will be able to:
  • Design and build a simple electrical circuit.
  • Explain the flow of electricity.
  • Explain the function of each component.
• Success Criteria:
  • All students can identify and label the components of a simple circuit.
  • Most students can contrast between open and closed circuits.
  • Some students can give real-life examples.
• Vocabulary:
  • Electric circuit
  • Electric current

Exploration and Explanation

• How do electric particles flow?
• Simple circuits are the basis of even the most complicated circuit.
• A circuit must have certain characteristics to allow electric particles to flow.
• An electric circuit is the flow of the electric current in a closed path to and from a source of electric energy.
• All simple circuits contain:
  • A source of electric energy.
  • An electric device.
  • An electric conductor.

Open and Closed Circuits

• A switch is often included in a circuit.
• A closed circuit is a complete circuit, and energy flows through the circuit.
• An open circuit is not a complete circuit; electric energy does not flow through an open circuit.

Elaboration

• Explain the flow of electric current in a circuit.
• Success Criteria:
  • All students can define electric current.
  • Most students can predict and explain the effects of adding or removing components in a circuit.
  • Few students can describe how electricity flows through a circuit.
• Website:
  • http://phet.colorado.edu/sims/html/circuit-construction-kit-dc-virtual-lab/latest/circuit-construction-kit-dc-virtual-lab_en.html

Solve Differentiated Questions

• Level 1: Model and label an electric circuit.
• Level 2: Contrast between open and closed circuits.
• Level 3: Relate each part of the circuit and its importance.

Factors Affecting Electric Current

• Several variables may affect the function of an electric circuit.
• We will study the effect of Voltage and Energy on an electric current.
• The amount of current affects the brightness of a light bulb, so it is important to know how to adjust the amount of current.

Voltage

• In the figure below, a battery creates an electric current in a closed circuit.
• Energy stored in the battery moves charged particles in the circuit. As the charged particles move through the circuit, the amount of energy transferred by the circuit depends on the battery’s voltage ($V$).
• Voltage is the electrical potential energy difference between two places on a circuit.
• Volts ($V$) are the measure of the potential energy difference.
• The 3 $V$ battery has a potential energy difference of 3 $V$ between the positive and negative side.
• A circuit with a high voltage source transfers more electric energy to other energy forms than a circuit with a low voltage source.
• For example, a light bulb connected to a 6-$V$ battery produces about two times the light and thermal energy than the same light bulb connected to a 3-$V$ battery.
• Voltage is often used as a shorthand term for voltage difference, which is another name for potential difference.
• Voltage measures the energy that a charge will get if it moves between two points in space.
• The unit for voltage is the volt ($V$).

Energy

• Electric circuits transfer electric energy to devices that change it to other forms of energy, such as light energy and thermal energy.
• Voltage shows how much energy changes in a part of a circuit.
• Although most of the energy changes in the intended devices, some energy is changed to thermal energy in the conductors.
• Copper is one of the best conductors, so charges move easily in it. It should transfer most of the electric energy to the devices and only change a small amount into thermal energy.

Explore Electric Circuit

• Electric circuit: is the flow of the electric current in a closed path to and from a source of electric energy.
• A closed circuit is a complete circuit, and energy flows through the circuit.
• An open circuit is not a complete circuit. Electric energy does not flow through an open circuit.
• A switch is used to change a circuit between open and closed.
• Electric current is the movement of electrically charged particles.
• Voltage is the electrical potential energy difference between two places on a circuit.
• Volts ($V$) The measure of the potential energy difference.

Group Work Answers

• 1. C) Each bulb will be dimmer than the first bulb was.
• 2. D) Is more energy transformed in an electric circuit in a light bulb or in a wire?
• 3. B) Charged particles move through a conductor.
• 4. A) disconnecting a wire, C) removing the battery, E) opening a switch
• 5. True
• 6. D) battery
• 7. True
• 8. A) The light bulb burns brighter because the current will be larger.
• 9. current