Planning a Solution

Engineering — Design Process | Unit 1, Lesson 3 of 6

📚 Grade: 3rd Grade⏱️ Duration: 45–60 minutes🛠️ Subject: Engineering — Design Process

✏️📐🗂️

Engineers compare more than one plan before choosing what to build.

📋 NGSS Standard:
3-5-ETS1-2 — Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.

🎯 Learning Objective

Students will sketch and compare at least two possible protective designs before choosing one to build.

💡 The Big Idea

Planning helps engineers test ideas on paper first. Comparing more than one possible solution leads to smarter building choices.

🔬 The Science

Science Snapshot

Plans are stronger when every feature is tied to a reason.

What is happening?

A plan is more than a picture. It should show how the parts of the design fit together and how the design is expected to solve the problem.

Why it works that way

Planning matters because it lets students think through force, support, and protection before they use materials. A clear plan also makes it easier to compare the original idea with what actually happened during testing.

Look for this in the lesson

Students should label each feature and explain its job. That makes the plan a scientific prediction rather than a decorative sketch.

Ask while you read: What feature in your plan is supposed to protect the fragile object most directly?

Materials

🏠 Household Items to Gather

Printed lesson pages and worksheet
Pencil and colored pencils
Previous notes from Lessons 1–2
Optional: sample materials to look at while sketching

📋 Printables

Student Worksheet page from this lesson

Let's Get Started

Step 1 — Review the Challenge Requirements: Remind students that their design must protect a fragile object and fit the known constraints.

Step 2 — Sketch Two Ideas: Students draw two different ways to protect the object during a drop.

Step 3 — Label Important Features: Add notes showing where the design cushions, supports, or holds the object.

Step 4 — Compare the Ideas: Use the criteria and constraints to decide which idea is more likely to succeed.

Step 5 — Choose the Best-Fit Plan: Students circle one design and explain why they chose it.

Discussion Questions

Why should engineers sketch before building?Look for answers like: Sketching helps them think through how a design might work before using materials.

Why is it useful to make two different plans?Look for answers like: It gives engineers options to compare instead of committing too quickly.

What is a tradeoff in this challenge?Look for answers like: One design may be stronger in one way but weaker in another, such as more padding but more weight.

Why should labels be added to a sketch?Look for answers like: Labels explain what each part is supposed to do.

How can the criteria help you choose between two plans?Look for answers like: They show which plan is more likely to meet the success goals.

Extensions

Extension: Sketch a third “wild card” idea and compare it to your chosen plan.

Extension: Ask a family member which of your two plans looks stronger and why.

Parent/Teacher Notes

Teaching note: Students do not need perfect art. The goal is readable engineering thinking.

Teaching note: Push them to compare plans using criteria and constraints, not only personal preference.

Student Worksheet

Name: ________________________ Date: ________________________

1️⃣ Sketch Idea A

2️⃣ Sketch Idea B

3️⃣ Compare and Choose

Plan	One strength	One possible weakness
Idea A
Idea B

I chose __________________ because ______________________________________.

✂️ PARENT ANSWER KEY — Detach before giving worksheet to students

1️⃣–2️⃣ Sketches — Sample Use

Accept any two reasonable protective design ideas that connect to the challenge and constraints.

3️⃣ Compare and Choose — Sample Response

A strong answer names a clear strength and weakness for each design, then chooses one using the criteria or constraints.

Model Response

“I chose Idea B because it keeps the object centered and has padding on more sides, even though it may use a little more material.”

✅ What Success Looks Like

Student creates at least two possible solutions.
Student compares them using engineering reasons.
Student chooses one plan and explains the choice.

🛠️ Troubleshooting / Teaching Notes

If the student says both plans are “good,” ask what job each one does better or worse.
If labels are missing, ask the student to mark where cushioning, support, or holding happens.