In this lesson students learn how to solder wires safely and confidently. Soldering is a core maker skill because it allows us to create strong, reliable electrical connections that won’t fall apart when a circuit is handled or moved. Students review essential shop safety rules, learn how a soldering iron works, practice tinning the iron and wires, and make their first soldered wire connection. The tone stays warm and supportive, helping students feel calm, respected, and safe while learning a tool that can feel intimidating at first.

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Student Learning Goals
By the end of this lesson students will be able to:
• Describe what soldering is and why we use it to join wires
• Follow all safety procedures for using a soldering iron
• Properly tin a soldering iron tip
• Strip, tin, and join wires together
• Hold their work still while solder cools
• Test a soldered connection using a multimeter

Materials Needed
Soldering irons with stands
Solder (rosin core)
Wire strippers
Pre-cut wires
Soldering sponge or brass cleaner
Small fan or open window for ventilation
Battery box and multimeter for testing
Safety glasses
Journals and pencils

Teacher Preparation Notes
Review the soldering safety test and ensure students have earned permission before participating. Prepare a clearly ventilated area with soldering stations spaced apart. Pre-tin one iron so you can show students what a correctly tinned tip looks like. Have sample wires prepared to demonstrate each step. Review slide safety notes so you can explain expectations calmly.

Safety Notes
We treat every soldering iron as hot at all times.
We keep fingers away from the iron tip and hot solder.
We tie back long hair and remove loose clothing or jewelry.
We wear safety glasses while soldering.
We solder only with teacher permission and supervision.
We unplug the soldering iron and place it in its stand when finished.
We work in a well-ventilated area with a small fan or open window.
We report any burns or injuries immediately.

Warm Up Activity
Ask students:
What do you think soldering does that twisting wires cannot do?
Let a few students guess. Explain that soldering creates a permanent, strong, low-resistance connection.

Lesson Flow

Step One: Safety Review

Walk through the safety slides slowly. Reassure students that soldering is safe when done thoughtfully. Emphasize:
• Never touch the iron tip
• Keep hands clear of hot solder
• Always place the iron in its stand
• Use ventilation

Journal prompt:
Write one safety rule you think is most important.

Step Two: Understanding the Tools

Show the parts of the soldering setup:
• Soldering iron
• Solder
• Sponge or brass cleaner
• Wires to be joined

Explain that solder melts quickly and hardens quickly, so we must work calmly.

Step Three: Tinning the Iron

Demonstrate how to:
• Clean the iron tip on a damp sponge
• Add a thin, shiny layer of solder to the tip
Explain that tinning helps the iron heat the wires evenly.

Let students watch closely before trying this step.

Step Four: Strip and Prepare the Wires

Students use wire strippers to remove about 3/8 inch of insulation.
Explain that the copper should stay bright and clean.

Step Five: Tinning the Wires

Guide students to:
• Touch the iron to the exposed wire to warm it
• Touch solder to the wire (not the iron) so it melts smoothly into the strands

Reassure them that practice makes this step feel easier.

Step Six: Solder the Wires Together

Students overlap their tinned wires.
Demonstrate how to:
• Heat the wires from below
• Apply a tiny amount of solder
• Hold the joint still while it cools

Explain that moving the wires will weaken the connection.

Step Seven: Clean the Iron and Place It Safely

Students clean the tip and place the iron back into its stand.
Remind them again that the iron stays hot for a while.

Step Eight: Test the Connection

Students use a multimeter to check their soldered joint:
• Set the meter to DC Voltage 20V
• Connect one probe to each end of the soldered wire
• Observe voltage from the battery box

A good joint will show a steady reading.

Journal prompt:
What did your multimeter reading tell you about your solder joint?

Teacher Notes for Each Slide
Slide 1 Title: Calm introduction.
Slides 2–5 Safety rules: Move slowly and answer questions.
Slides 6–10 Iron use: Reinforce hot tool safety.
Slides 11–18 Tinning wires: Demonstrate multiple times.
Slides 19–24 Joining wires: Encourage patience.
Slides 25–end Multimeter testing: Support careful probe handling.

Independent or Group Activity
Students create a small practice piece with three soldered joints in a row. They test each one and label them in their journals as “Strong,” “Weak,” or “Needs Work.”

Vocabulary and Concepts
Solder A metal alloy that melts and bonds wires
Tinning Adding a thin layer of solder for better heat transfer
Joint The connection between two soldered wires
Ventilation Moving air to remove fumes

Wrap Up
Ask:
What part of soldering felt easiest today?
What part should we practice again another day?

Exit Ticket
Write one safety rule you will always follow while soldering.

Quiz

  1. Why do we tin the iron?
  2. How much insulation do we strip from the wire?
  3. Why must we keep the wires still while solder cools?
  4. What tool do we use to check our finished joint?
  5. Why is ventilation important while soldering?

Teacher Reflection
Which safety rules did students remember easily?
Did they feel confident tinning the wires?
Should we plan an extra practice day before future soldering work?