Parallel Pathways

Overview

In this eighth lesson of “Circuits, Current, and Creativity,” students use the uploaded battery quiz and circuit images to compare series and parallel circuits. They construct or diagram branches, predict what happens when one branch is disconnected, and support an explanation with evidence from circuit behavior.

Learning intentions

Students will be able to:

• Compare the structure and current paths of series and parallel circuits.
• Construct or accurately diagram a simple parallel circuit.
• Predict the effect of disconnecting one branch.
• Use circuit images and observations as evidence in a written explanation.

Success criteria

• I can identify whether a circuit is series or parallel and explain why.
• I can show more than one complete path for current in a parallel circuit.
• I can predict what happens when one branch is disconnected and explain my reasoning.
• I can use evidence to compare parallel and series circuits.

Curriculum links

• Washington State science and literacy expectations: students interpret visual models and circuit images to obtain and communicate information.
• Reading in Science and Technical Subjects: use diagrams, symbols, and visual information to understand circuit structures.
• Writing in History/Social Studies, Science, and Technical Subjects: write an evidence-based explanation using clear claims and appropriate reasoning.
• Mathematical connections: represent positive and negative changes in circuit conditions and describe how a change affects the system.

Lesson structure (40 minutes)

1. 0–5 min · Hook and retrieval. Open with the hook and battery quiz slides and display two circuit images from the uploaded materials: one series and one parallel. Students complete three quick battery-quiz questions independently, then identify one visible difference between the circuits with a partner.

2. 5–11 min · Build the idea. Use the series-versus-parallel teaching slides to model current paths with arrows. Emphasize that a series circuit has one continuous path, while a parallel circuit has branches that provide multiple paths; avoid suggesting that current is a substance being “used up.” Students trace each possible path on the projected diagrams and explain their observations to a partner.

3. 11–20 min · Construct or diagram. Distribute the parallel circuit investigation sheet and provide circuit components to pairs. Students either build a circuit with a battery, switch, wires, and two bulbs, or draw the circuit if materials are limited. They label the battery, switch, branches, and bulbs, then check that each branch forms a complete path. Teacher circulates, asking, “Where can current travel if this branch is open?”

4. 20–28 min · Test the prediction. Refer to the investigation procedure and prediction slides. Before disconnecting one branch, students record a prediction and a reason on the worksheet. Pairs open one branch, observe the other branch, reconnect it, and then repeat the thought experiment for a series circuit using the uploaded circuit images. Students record observations using precise statements such as “the other bulb remains on” or “the entire circuit stops.”

5. 28–35 min · Evidence discussion and writing. Display the evidence discussion and writing prompt slides. Pairs compare results and identify evidence that supports or challenges their predictions. Each student writes a short claim-evidence-reasoning response: “A parallel circuit behaves differently from a series circuit because…” Teacher listens for the connection between multiple paths and the effect of an open branch.

6. 35–40 min · Plenary and exit check. Show the final comparison and exit prompt. Students complete the final worksheet questions: draw a parallel circuit, mark the branch that is disconnected, predict what remains working, and explain why. Invite two students to share contrasting explanations, then collect responses for review.

Resources

• Teacher-provided uploaded battery quiz
• Teacher-provided series and parallel circuit images
• the complete parallel circuit investigation deck
• the parallel circuit investigation sheet
• Batteries, battery holders, wires, switches, and two small bulbs per pair
• Optional circuit symbol and component reference cards
• Document camera or projector
• Pencils, colored pencils, and safety goggles
• One completed teacher circuit for demonstration

Assessment

• During retrieval and modeling, check whether students distinguish one path from multiple paths and correctly trace a complete circuit.
• During construction, use questioning and observation to assess safe handling, accurate branch diagrams, and the quality of predictions.
• Use the written claim-evidence-reasoning response and exit questions to assess whether students explain the effect of disconnecting one branch rather than merely stating the result.

Differentiation

• Support students with a partially completed diagram, color-coded branch paths, a word bank containing series, parallel, branch, complete path, and disconnected, and sentence starters such as “When one branch is open, ___ because ___.”
• Pair students strategically and assign roles such as builder, recorder, tester, and reporter; rotate roles so all students engage with the model and explanation.
• For EAL students and students with reading or writing needs, preview the circuit images, allow oral rehearsal before writing, and accept a labeled diagram plus dictated or speech-to-text explanation.
• Challenge students to design a parallel circuit with three branches and predict the result of disconnecting one, two, or all branches. Ask them to explain why parallel circuits are useful in homes and buildings, while noting that real household circuits require additional safety features.