Overview
This lesson helps students explore one of the most important ideas in electronics: some materials allow electricity to flow easily, while others block it almost completely. Students learn the meaning of conductivity and resistivity, see how wires and insulators work together, and then conduct hands on experiments using a battery pack, multimeter, and everyday objects around the room. The goal is to build confidence by letting students test and discover the properties of materials themselves.
Student Learning Goals
By the end of this lesson students will be able to:
• Explain the difference between conductivity and resistivity
• Describe why wires have metal cores and insulating coatings
• Safely set up a simple circuit for testing materials
• Use a multimeter to check whether electricity can flow through an object
• Record and compare their observations in their journal
• Build curiosity about how electricity behaves in the real world
Materials Needed
Battery boxes with batteries installed
Multimeters
Alligator clip leads
Various test objects (metal items, rubber pieces, plastic objects, water, pencil graphite, coins, paper clips, etc.)
Journals and pencils
Safety glasses
Teacher Preparation Notes
Test your setup before class: battery box to multimeter should show a clear voltage reading. Gather a basket of objects for students to test. Include a mix of conductive and non conductive materials. Arrange tables so students have space to experiment safely.
Multimeter reminder: we are only testing small DC circuits today. There is virtually zero risk of electrical shock when using a battery box and multimeter correctly.
Safety Notes
We always keep fingers behind the probe guides.
We handle alligator clips gently so they do not snap on skin.
We only use the materials provided by the teacher.
There is virtually zero shock risk using a single battery pack and multimeter when instructions are followed.
We keep water containers closed when not being tested.
We clean up spills immediately.
Warm Up Activity
Hold up a rubber object and a metal object. Ask students:
Which one do you think electricity can travel through Why
Let students guess. Do not correct them yet. Tell them they will discover the answers through testing.
Lesson Flow
Step One: Understanding the Words
Use the slides to introduce two important ideas:
Conductivity means electricity can move through a material.
Resistivity means the material slows or blocks electricity.
Give simple real world examples: metal spoon versus wooden spoon.
Ask students to write in their journals:
What everyday objects might conduct electricity
Step Two: Wires as the Perfect Example
Show the wire slide. Explain that wires have a metal center (for conductivity) and a rubber or plastic coating (for safety). This combination allows electricity to travel safely from one point to another.
Teacher note: This is a good moment to remind students that they already use conductive materials every day without realizing it.
Step Three: Setting Up the Test Circuit
Demonstrate how to:
Connect the battery box to the multimeter using alligator clips.
Set the multimeter to DC Voltage on the 20 volt range.
Observe the reading when the circuit is complete.
Explain that the multimeter shows numbers only when electricity is flowing.
Step Four: Testing Known Materials
Start with water and rubber, just like the slides.
Have students touch the clips to a container of water (carefully) and observe the reading. Then test rubber.
Journal prompt:
Record the voltage reading for each material.
Step Five: Free Exploration
Give students a basket of test materials. Allow them to test each one and record whether it is conductive or resistive.
Encourage them to try:
Coins
Paper clips
Aluminum foil
Plastic pieces
Graphite pencil lead
Fabric
Copper wire
Teacher note: Walk around the room and support students. Celebrate their discoveries.
Step Six: Group Sharing
Let each group share two surprising results. Students often think water is not conductive or that shiny objects are always conductors. Encourage curiosity.
Teacher Notes for Each Slide
Slide 1 Title: Introduce conductivity and resistivity.
Slides 2 to 5 Conductivity visuals: Explain simply.
Slides 6 to 10 Wire example: Show real wire if you have one.
Slides 11 to 13 Multimeter setup: Demonstrate slowly.
Slides 14 to 20 Water and rubber readings: Re create these results live.
Slides 21 to end Open exploration: Encourage safe experimentation.
Independent or Group Activity
Have groups create a simple chart in their journals with two columns: Conductors and Insulators. They test as many classroom objects as possible and fill in the chart.
Vocabulary and Concepts
Conductor A material that allows electricity to flow
Insulator A material that blocks or resists electricity
Resistivity How strongly a material opposes electrical flow
Circuit A complete path for electricity to travel
Voltage A measure of electrical pressure in a circuit
Wrap Up
Ask students:
What surprised you today
Why do you think wires must be both conductive and insulated
Let students reflect freely.
Exit Ticket
Write one conductor you tested and one insulator you tested.
Or draw a simple circuit showing where the electricity flowed.
Quiz
- What is conductivity
- What is resistivity
- Which part of a wire conducts electricity
A. Metal core
B. Plastic coating - What tool did we use to measure electrical flow
- Name one material that conducted electricity in your experiment.
Teacher Reflection
Which materials confused students
Did students handle the multimeter safely
Would you add more test items next time