# Defining a Problem with Criteria and Constraints

Defining a problem is the first step in the engineering design process. For kids in third, fourth, and fifth grades, this should include criteria and constraints. Let’s take a look at how teachers might introduce and reinforce it.

## Defining a Problem – The First Step in the Engineering Design Process

Our favorite fourth grade teacher sat at the side table with her student teacher. “As we begin the school year,” Ms. Sneed said, “we’ll introduce the engineering design process.”

As she spoke, she pointed to the screen of her laptop. “Here you see the Next Generation Science Standards for third through fifth grades. Today we’ll focus on the first one:

3-5-ETS1-1 Define a simple design problem reflecting a need or want that includes specified criteria for success and constraints on materials, time, or cost.

“Wow,” Mr. Grow replied, “defining a problem seems a little complicated.”

Ms. Sneed nodded. “Yes. But we’ll take a step-by-step approach. Then our kids will really get it.”

### Introduction to Defining a Problem with Criteria and Constraints

Ms. Sneed continued, “Sometimes teachers are tempted to jump into a fun STEM project during the first week of school. Many times, however, kids don’t really use or understand the steps in the engineering design process. Instead, I like to address each step explicitly.”

“Take a look at this story,” she said. She handed him the first two pages of “Calvin Builds a Guinea Pig.”

When he was finished reading, Mr. Grow looked up. “Wow,” he said again. “This little story definitely helped me understand about defining a problem. Specifically, I see how to identify criteria and constraints. Actually, explained like this, it’s easy!”

Ms. Sneed smiled. “Yep. The problem, or goal, simply stated, is to build a guinea pig cage. Criteria, or parameters for success, include size and other needs. On the other hand, constraints involve materials, time, and cost.”

As she spoke, Ms. Sneed jotted the definitions on a small piece of paper:

Criteria – needed for success

Constraints – limitations of materials, time, or cost

### Practice Defining a Problem with Criteria and Constraints

“Once kids understand the difference between criteria and constraints, they need some practice.” Ms. Sneed handed her student teacher another page. “In addition to reading, we’ll give kids time to stop and practice. On this page, kids read the situation and practice this step in the engineering design process.”

“Ah, I see. The paragraph simply states the situation. Then kids practice defining the problem and listing the criteria and constraints.”

“Exactly.”

### A Science Resource That Lets Kids Practice the Engineering Design Process

Ms. Sneed turned back to her laptop. “So,” she said, “we use the story to introduce the steps. However, I like using one additional resource to reinforce them.”

With one click, she opened a file. “This resource fulfills our science standard on reducing impacts of natural earth processes on humans. But at the same time, it gives kids practice the engineering design process. In other words, we integrate engineering design and science.”

### Practice Discriminating Between Criteria and Constraints

Ms. Sneed scrolled through the lesson plans. When she got to the student worksheets, she stopped. “First,” she said, “kids practice discriminating between criteria and constraints. As you can see, this provides truly focused practice.”

### More Engineering Design Practice – Defining a Problem with Criteria and Constraints

After scrolling a bit farther, she came to a page entitled “The Farmer’s Field.”

“Next,” she said, “kids are faced with a real-life scenario.” She read it aloud:

The farmer’s land is lower than the surrounding farms. Therefore, runoff from their land runs onto hers. In most cases, this benefits her. However, when it rains too much, her fields flood. Naturally, when the farmer’s field floods, her crops are lost.

The farmer needs a solution that doesn’t cost too much or take too much of her time. She wants runoff to continue, but she doesn’t want her field to flood. The solution can’t harm her crops in any way, and it must be legal. The materials need to be easy to get as well.

“So,” said Mr. Grow, “kids read the situation. Then they work on defining the problem. After that, they identify criteria and constraints. This is such great practice.”

## Enjoy Teaching

Ms. Sneed sat back in her chair and smiled. “Yep. Although it takes some doing, it works! When we focus on one step in the engineering design process at a time, kids learn better. And I enjoy teaching even more.”

Mr. Grow nodded. “Me too. Especially when I discover that defining a problem with criteria and constraints isn’t as hard as it seems!”

“Next,” Ms. Sneed continued, “we’ll teach kids to generate solutions. Then they’ll develop prototypes. And finally, students will learn how to conduct a fair test in engineering. That way, they’ll be ready for the ten STEM challenges I like to through out the year.”