Grade 9 Physical Sciences Lesson Plan: Finding Resistance of Resistors Using Colour Codes

by

Lesson Plan Title:

Grade 9 Physical Sciences Lesson Plan: Finding Resistance of Resistors Using Colour Codes

Materials Needed:

  • Resistors with colour codes
  • Colour code chart (printed or interactive digital version)
  • Multimeters (optional)
  • Worksheets with practice problems
  • Whiteboard and markers
  • Projector and computer (if using digital resources)
  • Notebooks and pens

Learning Objectives:

By the end of this lesson, students should be able to:
1. Identify and interpret the colour codes on resistors.
2. Calculate the resistance of a resistor using the colour codes.
3. Explain the significance of resistor tolerance.

Vocabulary:

  1. Resistor – A component that limits the flow of electric current in a circuit.
  2. Resistance – The opposition that a resistor offers to the flow of electric current, measured in ohms (Ω).
  3. Colour Code – A system of colours used to indicate the value and tolerance of resistors.
  4. Tolerance – The percentage that indicates how much the resistor’s actual resistance can vary from its stated value.
  5. Ohm (Ω) – The unit of electrical resistance.

Previous Learning:

Students should have a basic understanding of electric circuits, including the concepts of voltage, current, and resistance, as well as familiarity with basic circuit components such as resistors, batteries, and wires.

Anticipated Challenges and Solutions:

  • Confusion with Colour Codes: Provide a colour code chart and practice problems; also use a mnemonic to aid memory.
  • Difficulty Reading Small Resistors: Use larger resistors for demonstration and provide hand lenses if needed.
  • Mathematical Computation Errors: Offer step-by-step guidance and check for understanding throughout the practice problems.

Beginning Activities (6 minutes):

  1. Introduction to Objectives (3 minutes)
  2. Briefly explain the aim of the lesson and what students will learn.
  3. Show a resistor and ask if anyone knows what it is and what it does.
  4. Activating Prior Knowledge (3 minutes)
  5. Ask a few questions to recall students’ previous knowledge about circuits and components.
  6. Discuss how resistors are used in circuits.

Middle Activities (48 minutes):

  1. Direct Instruction (10 minutes)
  2. Explain the colour code system for resistors (using a projector or whiteboard).
  3. Show examples of different resistors and their colour codes.
  4. Introduce the tolerance bands and explain their significance.
  5. Guided Practice (18 minutes)
  6. Work through several examples as a class, using the colour code chart to determine resistor values.
  7. Write the steps on the board and solve them together.
  8. Use printed or digital colour code charts to assist with explanation.
  9. Hands-On Activity (20 minutes)
  10. Distribute resistors to students and have them determine the resistance using the colour codes.
  11. Rotate around the class to assist and ensure everyone is on track.
  12. Optionally, use multimeters to measure the actual resistance and compare it with calculated values.

End Activities (6 minutes):

  1. Exit Ticket Activity (6 minutes)
  2. Ask students to complete a quick worksheet where they decode the colour codes of a few resistors and write down their resistance values.
  3. Collect worksheets to assess understanding.

Assessment and Checks for Understanding:

  • Observe students during guided practice and hands-on activities, offering immediate feedback.
  • Use the exit ticket worksheets to assess students’ grasp of the lesson.
  • Ask questions throughout the lesson to ensure students are following and understanding key concepts.

Differentiation Strategies for Diverse Learners:

  • Scaffolding: Provide step-by-step guided examples before having students work independently.
  • Extension Activities: For advanced learners, introduce the calculation of total resistance in series and parallel resistor networks.
  • Support for Struggling Students: Pair up students for the hands-on activity and allow additional time if needed; use more visual aids and simplified explanations.

Teaching Notes:

  • Emphasise the importance of accuracy in reading the colour codes and calculating resistance.
  • Encourage the use of mnemonics for remembering the colour sequence.
  • Make sure all students can see the colour code chart clearly, whether digital or printed.
  • Ensure all materials are accessible for students with disabilities, including large-print charts or magnifying tools for those with visual impairments.

By structuring the lesson in this way, students will gain a thorough understanding of how to determine the resistance of resistors using colour codes and apply this knowledge practically in lab settings.