Improving the Design

Engineering — Design Process | Unit 1, Lesson 5 of 6

📚 Grade: 3rd Grade⏱️ Duration: 45–60 minutes🛠️ Subject: Engineering — Design Process
🔁📈🪛
Engineers redesign by changing the part that evidence shows needs improvement.
📋 NGSS Standard:
3-5-ETS1-3 — Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.

🎯 Learning Objective

Students will revise version 1 into version 2 by making an evidence-based improvement and predicting how it should work better.

💡 The Big Idea

Redesign is not starting over randomly. Engineers use evidence from testing to decide what should change in the next version.

🔬 The Science

Science Snapshot
test evidencechoose weaknesschange one featureimproved prototype
The best redesigns are targeted responses to evidence, not random changes.

What is happening?

Improvement means using evidence from the first test to make the design more effective. Engineers rarely expect the first version to be the final version.

Why it works that way

A smart improvement targets a specific weakness. If the object moved around too much, the design may need a better holder. If the structure collapsed, it may need more support or a different shape.

Look for this in the lesson

Students should connect each revision to one observed problem. That makes redesign logical instead of random.

Ask while you read: Which observed weakness should you fix first, and why?

Materials

🏠 Household Items to Gather

📋 Printables

Let's Get Started

Step 1 — Review the Failure Point: Re-read the evidence from Lesson 4 and identify the most important weakness to address.
Step 2 — Plan One Targeted Change: Choose one improvement that connects directly to the weak part of version 1.
Step 3 — Build Version 2: Create the revised prototype using the planned change.
Step 4 — Predict the Improvement: State what should work better in version 2 and why.
Step 5 — Compare Version 1 and Version 2: Explain how the redesign responds to the evidence from testing.

Discussion Questions

Why should version 2 connect to version 1 evidence?Look for answers like: Because redesign should fix a real weakness, not be random.
Why is it helpful to change one key part at a time?Look for answers like: It makes it easier to tell what actually improved the result.
What kind of change might help a weak side support?Look for answers like: Adding stronger support, more tape, or better balance.
Why should engineers predict what version 2 will do better?Look for answers like: It helps them connect the change to a reason and expected result.
How is redesign different from starting over with no plan?Look for answers like: Redesign uses evidence from the earlier test.

Extensions

Extension: Make a before/after sketch of version 1 and version 2 with labels for the changed parts.

Extension: Ask a family member whether your redesign makes sense and what evidence they want to hear.

Parent/Teacher Notes

Teaching note: Keep redesign focused. Too many changes at once make the evidence harder to use.

Teaching note: Use sentence frames if students struggle to explain why a change should help.

Student Worksheet

Name: ________________________     Date: ________________________

1️⃣ What Needed to Improve?

The failure point from version 1 was ______________________________________.

2️⃣ What Will I Change?

Part of the designMy changeWhy this should help

3️⃣ Predict Version 2

Complete the sentence: Version 2 should work better because ________.

✂️ PARENT ANSWER KEY — Detach before giving worksheet to students

1️⃣ What Needed to Improve? — Sample Use

Accept the failure point the student observed in Lesson 4 if it is specific and evidence-based.

2️⃣ What Will I Change? — Sample Ideas

Possible responses include adding more padding, strengthening a side wall, changing where the object sits, or improving how pieces are attached.

3️⃣ Predict Version 2 — Model Response

“Version 2 should work better because I added stronger side supports where version 1 bent during the drop.”

✅ What Success Looks Like

🛠️ Troubleshooting / Teaching Notes