Engineering Design and Innovation · Weeks 19-27

Defining Design Problems

Learning how to specify criteria and constraints for a successful design solution.

About This Topic

Engineering begins with a clearly defined problem. In this topic, fifth graders learn that before they can build a solution, they must understand the 'criteria' (what the solution must do) and the 'constraints' (the limits, like time, money, and materials). This is the foundation of the NGSS Engineering Design process.

Students practice identifying the needs of a 'user' and translating those needs into specific goals. For example, instead of just 'making a bridge,' they might define the problem as 'building a bridge that can hold 5 pounds, using only paper and tape, in 20 minutes.' This precision is what separates engineering from general crafting.

This topic comes alive when students can physically model the patterns of a problem and engage in peer interviews to uncover the hidden needs of a design challenge.

Learning Objectives

• Identify the key criteria and constraints for a given design problem.
• Analyze user needs to define specific requirements for a design solution.
• Critique a proposed design solution based on its ability to meet defined criteria and constraints.

Before You Start

Introduction to the Engineering Design Process

Why: Students need a basic understanding of the steps involved in engineering before focusing on the initial problem definition.

Observation and Questioning Skills

Why: The ability to observe carefully and ask relevant questions is fundamental to identifying user needs and defining problems.

Key Vocabulary

criteria	The specific requirements or standards that a design solution must meet to be considered successful.
constraints	The limitations or challenges that must be considered when designing a solution, such as time, materials, or cost.
user needs	The problems, desires, or requirements that the intended recipient of a design solution has.
design problem	A specific challenge that can be addressed through the creation of a new product, process, or system.

Active Learning Ideas

Role Play: The Client Interview

One student acts as a 'client' with a specific problem (e.g., 'I need a way to carry my cat on a bike'). The 'engineer' must ask questions to identify the criteria and constraints before they are allowed to sketch any ideas.

⏱ 30 min·Pairs

Generate mission

Think-Pair-Share: Constraint Sort

Give students a list of items (e.g., 'Must be waterproof,' 'Costs under $5,' 'Must be blue'). In pairs, they must sort these into 'Criteria' (goals) and 'Constraints' (limits) and justify their choices.

⏱ 20 min·Pairs

Generate mission

Collaborative Problem-Solving: The Playground Fix

Small groups walk around the school playground to find a 'problem' (e.g., a puddle that never dries). They must write a formal 'Problem Definition' that includes at least three criteria and two constraints for a potential fix.

⏱ 45 min·Small Groups

Generate mission

Real-World Connections

Product designers at companies like Apple must define precise criteria, such as 'a smartphone that can withstand a 3-foot drop onto concrete' and constraints like 'must use existing battery technology,' before developing new models.

Urban planners designing new public parks must interview community members to understand user needs, like 'safe play areas for young children' and 'accessible pathways for wheelchairs,' while adhering to budget constraints.

Automotive engineers developing electric vehicles must meet criteria for range and charging speed, while working within constraints of battery weight, cost, and available charging infrastructure.

Watch Out for These Misconceptions

Common Misconception

Engineering is just building things.

What to Teach Instead

Students often want to start building immediately. By using 'Client Interviews,' teachers can show that the most important part of engineering happens before you touch any materials, it's about understanding the problem correctly.

Common Misconception

Constraints are bad because they limit creativity.

What to Teach Instead

Students may see limits as annoying. Through peer discussion, they can learn that constraints actually help engineers focus their ideas and lead to more innovative, realistic solutions.

Assessment Ideas

Exit Ticket

Provide students with a scenario, such as designing a backpack for a hiker. Ask them to list two criteria the backpack must meet and two constraints the designer will face. For example, Criteria: Must hold 20 lbs. Constraints: Must be waterproof.

Quick Check

Present a simple design challenge, like creating a device to water a plant. Ask students to write down one question they would ask the 'user' (the plant owner) to understand their needs. Then, ask them to identify one possible constraint for this design.

Peer Assessment

Students work in pairs to define a design problem for each other, such as building a birdhouse. One student writes the problem statement, including criteria and constraints. The partner reviews it and provides feedback: 'Are the criteria measurable?' and 'Are the constraints realistic?'

Frequently Asked Questions

What is the difference between a scientist and an engineer?

Scientists ask questions about the natural world and look for answers. Engineers identify problems in the human-made world and design solutions. Scientists want to know 'why,' while engineers want to know 'how can we make this better?'

How can active learning help students define design problems?

Active learning, like the 'Client Interview' role play, forces students to practice communication and empathy. Engineering isn't done in a vacuum; it's done for people. By interacting with a 'client,' students realize that a successful design is one that meets specific, often hidden, needs. This social interaction makes the abstract concept of 'criteria' much more meaningful.

What are some common constraints for 5th grade projects?

Common constraints include a time limit (e.g., 30 minutes), a limited budget (e.g., only 10 pipe cleaners), or physical size (e.g., must fit inside a shoebox). These help keep the projects manageable and realistic.

Why do we need criteria?

Criteria are the 'success markers.' Without them, you won't know if your design actually worked. They give you a way to measure and compare different solutions to see which one is the best.