Electricity and Current in Circuits

Electricity

  • Flow of Electricity: Understanding the flow of electricity is essential when studying circuits.

Learning Objectives

  • Objective 1: Understand how electricity flows around a circuit.

  • Objective 2: Learn about the electrons that flow to create electric current.

Group Discussion

  1. Components of a Complete Circuit:

    • Identify which of the following must be present for current to flow:

      • Lamp

      • Cell

      • Switch

      • Wire

  2. What Flows in a Complete Circuit:

    • Voltage

    • Wire

    • Current

    • Heat

Current

  • Understanding Cells and Batteries:

    • A cell transforms chemical energy into electrical energy in a circuit.

    • A battery consists of two or more cells connected together.

    • Cells have two terminals, marked with symbols:

    • Positive (+)

    • Negative (–)

  • Flow of Electrons:

    • In a circuit, the negative terminal pushes electrons around the wires.

    • Definition of Current: The flow of electrons in a circuit.

More About Electrons

  • Electron Characteristics:

    • Electrons are negatively charged particles found in atoms.

    • In metals, some electrons are free to move.

    • When in a circuit, these electrons move towards the positive terminal.

    • **Attraction and Repulsion: **

    • Opposite charges attract, like charges repel.

    • Positive + Negative --> Attract

    • Positive + Positive --> Repel

    • Negative + Negative --> Repel

  • Circuit Continuity: Electrons only flow in a complete circuit. If there is a break, flow stops.

Assessment Questions

  1. Identify the particles that move in a circuit: Electrons.

  2. Fill in the blanks:

    • Current in a circuit is the movement of electrons.

    • These particles have a negative charge.

    • They are attracted by the positive terminal and repelled by the negative terminal.

Direction and Flow of Electrons

  • Choice Assessment: Determine the flow in a circuit:

    • A: From positive to negative terminal?

    • B: From negative to positive terminal?

    • Answer: B (Electrons flow from the negative terminal to the positive terminal).

  • If a switch is open, no current flows through.

Function of Circuit Components

  1. Why does the lamp light up?: Electric current flows through.

  2. Role of the switch:: To open/close the circuit.

  3. Source of electricity:: From the socket connected to a far power station.

  4. Current pathway:: Through wires.

  5. Wires' importance:: They carry current (not electricity).

Glossary

  1. Cell: Component that converts chemical energy to electrical energy (typically 1.5 V).

  2. Battery: Two or more cells in series.

  3. Components: Parts of a circuit (e.g., cells, lamps, switches).

  4. Terminals: Connection points on components, marked (+) and (-).

  5. Electrons: Negatively charged particles flowing to generate current.

  6. Current: The flow of electrons in a circuit.

  7. Negative Charge: Attracts to positive charges and repels negative ones.

  8. Free to Move: Electrons that can move within conductors.

  9. Attract: Pulls objects closer.

  10. Repel: Pushes objects apart.

  11. Voltage: Measurement of current strength in a circuit.

Scientific Inquiry

  • Experiment Objective: Make and test predictions about current flow in a circuit.

  • Set-Up Needed: Power supply or battery, long wires, and identical lamps.

Expected Observations

  • After powering on: All lamps will light up simultaneously based on circuit closure.

  • Flow of Electrons: They all begin to move together when the switch is closed, allowing current to circulate throughout the circuit.