MS-ETS1-1: Defining Precise Criteria and Constraints for a Design Problem
In plain English: MS-ETS1-1 is the NGSS middle school engineering performance expectation that asks students to define the criteria and constraints of a design problem precisely enough to ensure a successful solution. Students turn vague goals into measurable ones, use scientific principles to set limits, and weigh impacts on people and the natural environment. It is usually taught inside grades 6-8 science.
Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.
Next Generation Science Standards · Disciplinary Core Idea: Engineering Design · Official standard
Before engineers design anything, they define the problem: they write down exactly what a successful solution must do and what limits it must respect. A design problem is a need or a want that people try to meet by making something. A criterion (plural criteria) is something the solution must do or achieve to count as a success, such as "keeps the soil moist for 9 days". A constraint is a limit on possible solutions, such as cost, materials, size, time, safety rules or laws. A requirement is precise when it names a number with a unit, or a clear yes-or-no test, so anyone can check whether a design meets it. In this lesson, students define the problem of watering the class's bean plants over a 9-day break, then define two more problems on their own. They use scientific principles, ideas from science that predict how things behave (for example, open water evaporates faster in warm, sunny air), to set limits, and they think about who and what a solution could affect: people, and the natural environment of plants, animals, water and soil.
NGSS gives no Clarification Statement and no Assessment Boundary for MS-ETS1-1, so the lesson follows the wording of the performance expectation itself. The practice is Asking Questions and Defining Problems: students end with a written design brief, not with a built device. All plant, wick and survey data on this page are invented for teaching and labeled as invented. The wick test uses only tap water, cups and string.
Learning Objectives
By the end of this lesson, students will be able to:
Tell criteria (what a successful solution must do) from constraints (limits on possible solutions), and both from solution ideas
Rewrite a vague requirement as a precise one that names a number with a unit, or a clear test
Use a measurement or a scientific principle to decide the number in a criterion or a constraint
Identify potential impacts of a solution on people and on the natural environment, and write them as constraints
Write and critique a complete design brief for a new design problem
Prior Knowledge Required
Students should already be comfortable with:
Defining a simple design problem with criteria and constraints on materials, time or cost (3-5-ETS1-1)
Measuring volume in milliliters and mass in grams, and knowing that 1 mL of water has a mass of about 1 g
Evaporation: liquid water turning into water vapor, faster when it is warm and exposed to moving air
Finding the mean (average) of a small data set 6.SP.B.5
Show a photo of a wilted classroom plant after a long weekend. Tell students the class has 24 bean plants and a 9-day break is coming, with no one in the room.
Warm-Up Prompt
"Before anyone builds anything, what would we need to know to say that a plant-watering device worked? Write down two things it must do and two limits it has to stay within."
Collect answers on the board in two columns without labels. Students often write goals such as "waters the plants" and "not too expensive". Ask: "How would we know, on day 9, whether a device did this?" Keep the list: the lesson returns to it.
Direct Instruction15-20 minutes
Criteria, constraints and precision. Define design problem, criterion, constraint, precise and scientific principle (see the overview). Label the warm-up columns "criteria" and "constraints". Then show how to make each requirement precise by asking three questions: What number or test? What unit? How will we check it? Use Diagram 1 as the finished design brief for the plant problem, and build it with the class through these examples.
From a vague goal to a precise criterion
Vague: "The device should keep the plants watered." The week before, the class weighed a watered bean plant in its pot each morning and found it lost about 25 g of water a day (invented data), which is about 25 mL. The break lasts 9 days.
Result: Each pot needs about 9 × 25 = 225 mL over the break. Precise criterion: "At least 225 mL of water reaches each pot over 9 days, and no plant is wilted on day 9." Both parts can be checked with a measuring cup and a look at the leaves.
Constraints with numbers: cost and size
The class has $72 to spend on 24 planters. The windowsill where the plants sit is 18 cm deep, and each planter must be built in one 45-minute class period.
Result: Cost: $72 ÷ 24 = $3, so "each planter costs no more than $3". Size: "no part sticks out past 18 cm from the window". Time: "built in one 45-minute period". Each is a limit, so each is a constraint.
A scientific principle sets a number
Some teams want an open dish of water as the reservoir. Open water evaporates faster in warm, sunny air. The class left an open dish of water, about 8 cm across, on the sunny windowsill and found it lost 8 mL a day (invented data); a bottle with its cap screwed on and one small hole in it lost almost nothing.
Result: An open reservoir must hold enough for the plant plus evaporation: 9 × (25 + 8) = 297 mL, so about 300 mL. A capped reservoir needs only 225 mL. The principle changes the number in the requirement.
An impact on people
The custodian will clean the room during the break, and water on a sill or floor can make someone slip. Cut plastic bottles can have sharp edges.
Result: Constraint: "A planter left on a dry paper towel for 24 hours leaves the towel dry" (a test anyone can run). Safety constraint: "Every cut edge is covered with tape."
An impact on the natural environment
After the break, leftover water is poured on the school garden, where earthworms and young plants live. New plastic adds to waste.
Result: Constraints: "The water contains no plant food or soap" and "Every planter is made from bottles and cups the class already has." Both limit what a solution may use, so both are constraints that protect the environment.
After each example, ask: "Is it a criterion or a constraint? What number or test makes it precise?" Point out that "use a cotton wick" is not a requirement at all; it is a solution idea, and writing it into the problem would rule out other good ideas too early.
Guided Practice15 minutes
Pairs judge six requirements that another class wrote for the same plant problem. For each one, they decide whether it is a criterion, a constraint or a solution idea, and whether it is precise. Then they rewrite every vague one.
Requirements written by another class (for discussion)
#
Requirement
Criterion, constraint or solution idea?
Precise?
1
The plants should be happy
2
Uses no electricity, since nobody can check a plug during the break
3
Uses a sponge to hold the water
4
Each plant's soil is still damp 2 cm below the surface on day 9
5
Not too heavy
6
The reservoir can be refilled by a student in under 1 minute
Sort the six. Discuss: is "uses no electricity" a criterion or a constraint? (A constraint: it limits the solutions, and the reason is a safety and supervision limit.)
Number 3 names one way to solve the problem. Why does it not belong in the problem definition?
Rewrite numbers 1 and 5 with a number, a unit or a test. For number 5, decide what the weight limit protects (the windowsill, a student who carries it) and choose a number that fits.
Share one rewrite with the class. The class checks it with the three questions: what number or test, what unit, how will we check it?
Independent Practice15-20 minutes
Each student writes a design brief for a new problem: a rain cover for the school's outdoor bike rack, which holds 12 bikes next to a walkway and a row of young trees. Facts for the brief (invented): bikes stand in a row 7 m long; rain usually blows in from the west; the walkway must stay at least 1.5 m wide so wheelchair users can pass; the tree roots spread under the area beside the rack; the parent group can give $400.
The brief must include at least two precise criteria, two precise constraints, one scientific principle and how it sets a number or test, one impact on people and one impact on the natural environment. Students swap briefs with a partner and mark any requirement that is vague or is really a solution idea.
Closure5 minutes
Exit ticket: "A team writes: 'The planter should look nice.' Is it possible to make this precise? Write a version that could be checked, or explain why the team should drop it." (One good answer: "At least 3 of every 4 classmates rate it 3 or higher on a 1-5 scale.") Return to the warm-up list and ask which items the class has now made precise.
Teacher note: this standard ends with a defined problem, not a finished device. Building and testing belong to MS-ETS1-2, MS-ETS1-3 and MS-ETS1-4, so the wick test here is a measurement used to choose a number, not a contest.
Differentiation Strategies
For Struggling Students
Give a two-column organizer headed "must do (criteria)" and "limits (constraints)", with the three precision questions printed at the top
Provide sentence frames: "The solution must ___, measured by ___" and "The solution may not ___, because ___"
Start with the cost and size constraints, where the number comes straight from a fact, before writing criteria that need a measurement
For Advanced Students
Ask students to add a safety margin to a criterion (for example, design for 30 mL a day instead of 25) and explain which scientific principle makes warm days riskier
Have students find two requirements in their brief that pull against each other, such as a low cost and a large reservoir, and explain how a precise number in each helps the team find a design that meets both
Ask students to interview a real stakeholder (the custodian, a gardener) and add one requirement the class had missed
Assessment Guidance
What to Look For
Check that students separate what a solution must achieve (criteria) from the limits it must respect (constraints), and that they do not write solution ideas as requirements. Look for numbers with units and for tests anyone could run. Strong briefs connect at least one number to a measurement or a scientific principle and name impacts on both people and the natural environment. Watch for vague words that hide a missing number, such as "enough", "strong", "cheap" and "easy".
02
Classroom Activities
3 Activities
1
Vague to Precise: Requirement Card Sort
20 minPairs
Each pair gets 12 cards with requirements for the plant-watering problem. They sort the cards into three piles: criteria, constraints and solution ideas. Then they choose the vague cards and rewrite each one so it names a number with a unit, or a test.
The 12 Cards
Keeps every plant from wilting for 9 days
Costs no more than $3 per planter
Uses a cotton wick
Fits on an 18 cm deep windowsill
Waters the plants well
Made only from materials the class already has
Uses a bottle with a hole in the cap
Puts all the pots in one big tub of water
Cheap
Is built in one 45-minute class period
Easy to refill
Sends at least 25 mL of water to the pot each day
Procedure
Sort the cards into the three piles. Put a sticky note on any card the pair disagrees about.
Find the vague cards: words like "well", "cheap" and "easy" are clues. Rewrite each vague card on a blank card so it can be checked.
Compare piles with another pair and settle the sticky-note cards by asking: does it say what success looks like, does it limit the solutions, or does it pick a solution?
Discussion Questions
Three cards name solution ideas. Which are they, and what better requirement could replace each one?
Card 1 and card 12 are both criteria about water. Which is easier to test in the middle of the break, and which is the one that really matters?
Card 11 says "Easy to refill". What number or test would make it precise?
Modification for Distance Learning
Put the 12 cards on a shared slide with three labeled boxes. Pairs drag the cards into the boxes in a breakout room and type their rewrites into the speaker notes.
2
Wick Test: Measure Before You Set a Criterion
30 min, plus a 24-hour waitGroups of 3
Groups measure two things the plant problem needs: how much water a bean plant loses in a day, and how much water different wicks can carry in a day. A wick is a strip of fabric or string that water climbs through tiny gaps between its fibers, the way a paper towel soaks up a spill. The plant data set the number in the criterion; the wick data show which wick could meet it.
Procedure
Plant water loss: water three potted bean plants until water drips out, let them drain, and weigh each pot. Weigh again 24 hours later. The mass lost in grams is about the water lost in milliliters.
Wick test: put 200 mL of tap water in a cup raised on a stack of books, and an empty cup below it. Run one wick from the bottom of the full cup into the empty cup. Test one cotton string, three cotton strings twisted together, a 2 cm strip cut from an old cotton T-shirt, and one nylon string.
After 24 hours, measure the water in each lower cup with a measuring cylinder or a kitchen scale.
Safety: wipe up spills right away, and keep the cups away from outlets and computers.
Sample Data (invented)
Plant water loss in 24 hours: 23 g, 27 g and 25 g. Water moved in 24 hours: one cotton string 9 mL, three cotton strings 24 mL, T-shirt strip 31 mL, nylon string 2 mL (Diagram 2).
Discussion Questions
Use the mean plant water loss to write the criterion for a wick. Which wick meets it?
The three cotton strings moved 24 mL, just under the criterion. Should the team call that close enough? What could go wrong on a hot, sunny day?
The nylon string barely moved any water. What does that tell you about choosing materials, and does it belong in the problem definition or in the solution?
Challenge Variation
Groups repeat the wick test with the upper cup only 2 cm higher than the lower one, predict whether more or less water moves, and decide whether the criterion should also name the height difference.
3
Design Brief Challenge: The Pond Trash Catcher
25 minGroups of 4
A park pond near the school collects floating litter. Groups write the full design brief for a device that catches floating trash, using a fact sheet and notes from five stakeholders. Then they swap briefs with another group and check them.
Fact Sheet (invented)
Volunteers pick up about 60 floating items a week, mostly wrappers, cups and bottles shorter than 30 cm.
Ducks, turtles and small fish live in the pond. Turtles rest on logs near the east bank.
The wind usually blows from the west, so floating litter drifts to the east bank.
Things that are less dense than water float, so the litter stays at the surface, and a catcher must float too.
Stakeholder Notes
Park ranger: "It has to be emptied by one person in under 10 minutes a week."
Wildlife volunteer: "Nothing that could trap a duckling or a turtle."
Kayak club: "We paddle the middle of the pond every Saturday."
City budget office: "The park has $250 for this."
Neighbor: "Please don't make the pond look like a junkyard."
Procedure
Write at least three criteria and three constraints, each precise. Use the wind fact to choose a location, and the floating fact to set a material requirement.
Write at least two impacts on people and two on the natural environment, each as a constraint.
Swap briefs. The checking group asks four questions about every line: Is it precise? Is the test named? Is it a requirement, not a solution? Does it protect someone or something named on the fact sheet?
Discussion Questions
The wildlife volunteer's note is not a number. How did your group make it precise?
Which stakeholder note was hardest to turn into a requirement, and why?
Which scientific principle on the fact sheet changed your brief the most?
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: A Design Brief for the Plant-Watering Problem
The design problem in the middle, surrounded by the five parts of a complete definition: criteria (what success looks like), constraints (limits), the scientific principles that set some of the numbers, and the impacts on people and on the natural environment that the solution must respect. Every criterion and constraint names a number or a test.
Diagram 2: Water Moved by Four Wicks in 24 Hours (Invented Data)
Invented wick test data, drawn to scale. The red dashed line is the criterion set from the plant data: at least 25 mL per day. Only the T-shirt strip (31 mL) meets it. Three cotton strings (24 mL) fall just short, which shows why a precise number matters: "about enough" would have hidden the gap.
Directions: All data are invented for practice. For every requirement you write, include a number with a unit or a test that anyone could run, and say whether it is a criterion or a constraint.
Part 1: Criteria, Constraints and Precision (Problems 1-2)
The drama club wants a rolling rack for its costumes. Its list says the rack (a) carries 25 costumes on hangers, (b) costs less than $80, (c) is easy to push, (d) fits through a doorway 80 cm wide, (e) looks good on stage and (f) is built by the club in 3 weekends. Label each as a criterion or a constraint, mark the ones that are vague, and rewrite two vague ones precisely.
A class is designing a fish-food dispenser for a 4-day weekend. The food label says the fish need about 0.5 g of flakes a day, and uneaten food rots and uses up oxygen in the water. (a) Explain why the criterion should be a range, such as 0.4-0.6 g a day, instead of "at least 0.5 g a day". (b) Find the smallest and largest total the dispenser should release over the weekend. (c) Describe a test the class could run before the weekend.
Part 2: Using Data and Scientific Principles (Problems 3-4)
A team is designing a way to keep ice off the school's front steps on winter mornings, when the low is often -5 °C. Salt lowers the temperature at which water freezes, but salt that washes off harms lawns and the small stream next to the school. (a) Name the scientific principle the design relies on. (b) Write one precise constraint that protects the natural environment. (c) Write one precise criterion that protects people.
A team is designing a shelf for the class's 30 science binders. They weigh 5 binders: 1.2, 1.4, 1.1, 1.3 and 1.5 kg. (a) Find the mean mass and the total mass of 30 binders at that mean. (b) Write a load criterion that includes a safety margin of 1.5 times the total. (c) Which scientific idea explains why the shelf must be tested with a load and not just looked at?
Part 3: Impacts and Complete Briefs (Problems 5-6)
A team's design brief for a schoolyard bird feeder says: "Criteria: squirrels can't get the seeds; holds a lot of seed. Constraints: use a metal cone on the pole." (a) Find three problems with the brief. (b) Rewrite it with at least two precise criteria and two precise constraints. (c) Add one impact on people and one impact on the natural environment.
Write a complete design brief for a device that stops wind from blowing litter out of the school's outdoor trash cans. Include at least two criteria, two constraints, one scientific principle that sets a number, one impact on people (think about younger students and the custodian) and one impact on the natural environment (think about animals and storm drains).
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Criteria and Constraints
Every requirement is correctly labeled, and no solution idea is written as a requirement
One requirement mislabeled or one solution idea left in
Precision
Every requirement names a number with a unit or a test that anyone could run, with correct arithmetic
Some requirements are precise, but at least one stays vague or has an arithmetic error
Principles and Impacts
A scientific principle sets at least one number, and impacts on both people and the natural environment appear as constraints
Principle or impacts mentioned but not turned into requirements
05
Quiz: 20 Questions
Interactive, with answers
Instructions
All data are invented. Your score updates as you answer, and Reset quiz clears everything so you or your students can try again. Short-answer questions show a model answer; other precise answers can earn full credit.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
In a design problem, what is a criterion?
Answer: B
A criterion describes success: what the solution must do or achieve. Choice A describes a constraint. Choice C is a solution idea, which comes after the problem is defined, and choice D is part of designing, not defining, the problem.
Question 2 of 20 · Multiple Choice
A team is designing a recycling bin for the cafeteria. Which requirement is a constraint?
Answer: C
A cost limit rules out some designs, so it is a constraint. Choices A, B and D each describe what the bin must achieve, so they are criteria.
Question 3 of 20 · Multiple Choice
Which criterion for a phone stand is the most precise?
Answer: D
Choice D names a mass, an angle and a time, so anyone can test it. Choices A, B and C use vague words ("well enough", "very much", "strong enough") that different people would judge differently.
Question 4 of 20 · Multiple Choice
A team lists requirements for a device that keeps a hamster's water bottle full over a weekend. Which one is a solution idea, not a requirement?
Answer: A
Choice A picks one way to solve the problem, which would rule out other designs too early. Choice B is a precise criterion, and choices C and D are constraints that limit the solutions.
Question 5 of 20 · Multiple Choice
Seedlings in an open tray need 30 mL of water a day for 12 days. The open tray also loses 5 mL a day to evaporation. What is the smallest amount of water the tray must hold at the start?
Answer: C
Each day uses 30 + 5 = 35 mL, so 12 days need 12 × 35 = 420 mL. Choice A leaves out evaporation. Choice B is the amount for one day. Choice D adds the evaporation for only one day instead of all 12.
Question 6 of 20 · Multiple Choice
A class has $90 to build 30 desk organizers, and it has already spent $12 of it on tape. What is the most each organizer can cost to build from now on?
Answer: B
The money left is $90 - $12 = $78, and $78 ÷ 30 = $2.60 per organizer. Choice A ignores the money already spent. Choice C is the tape cost per organizer ($12 ÷ 30). Choice D adds that $0.40 instead of subtracting it.
Question 7 of 20 · Multiple Choice
A team is designing a hook to hang a flower basket from a porch beam. Which scientific principle best helps them set a criterion for how strong the hook must be?
Answer: C
The hook must hold the weight of the basket at its heaviest, just after watering, so the criterion depends on how hard gravity pulls on the full, wet basket. Choice A might matter for where to hang the basket, but not for the hook's strength. Choices B and D are true but do not affect the hook.
Question 8 of 20 · Multiple Choice
A team designs a new lid for the school's outdoor compost bin. Which requirement addresses an impact on people?
Answer: A
Choice A names who is affected and sets a test (one-handed opening), so it protects people who use the bin. Choices B and D are criteria about how well the lid works, and choice C is about the environment.
Question 9 of 20 · Multiple Choice
A town is designing a fence to keep deer out of a community garden next to a wetland. Which constraint protects the natural environment?
Answer: D
Choice D limits the design so that turtles moving between the wetland and the land are not blocked. Choice A is a criterion about keeping deer out. Choice B is a cost constraint, and choice C is about the people who use the garden.
Question 10 of 20 · Multiple Choice
A team is setting a criterion for a coat rack. They weigh five full backpacks: 4.2, 5.0, 6.1, 4.8 and 5.4 kg. Each hook must hold the heaviest backpack with a safety margin of 2 times. What load must each hook hold?
Answer: D
The heaviest backpack is 6.1 kg, and 2 × 6.1 = 12.2 kg. Choice A is the mean, which some backpacks are heavier than. Choice B doubles the mean, and choice C uses the heaviest backpack with no margin.
Question 11 of 20 · Multiple Choice
A team writes: "The fire drill alarm must be loud." Which rewrite makes this criterion precise?
Answer: B
Choice B names a distance and a condition, so the class can stand at the end of the hall and check it. Choices A and C only repeat "loud" in other words, and choice D compares with other alarms without saying how loud they are.
Question 12 of 20 · Multiple Choice
Why should a team define its criteria precisely before it starts testing designs?
Answer: A
Precise criteria let anyone check a design against the same test, which is what makes a successful solution possible to recognize. Choice B gets the purpose backward: criteria written after testing could be bent to fit any design. Choices C and D do not follow from precision.
Question 13 of 20 · Multiple Choice
A team designs a bright light to scare deer out of the school garden at night. Which requirement should they add because of an impact on people?
Answer: D
Neighbors could be kept awake, so the team adds a constraint that protects them. Choice A is a criterion about the deer. Choice B is a solution idea, not a requirement, and choice C is vague.
Question 14 of 20 · Multiple Choice
A screen that keeps litter out of a storm drain must let water through. In a heavy rain, about 12 L of water per second reaches the drain. In a test, a team's screen lets 9 L per second through. What does the test show?
Answer: B
The drain must pass 12 L per second, and 12 - 9 = 3 L per second would be left over, which backs up into the street, an impact on people and property. Choices A and D ignore the number in the criterion. Choice C throws out a criterion instead of using it.
Question 15 of 20 · Short Answer
A team writes one requirement for a model bridge: "The bridge should be strong and not too expensive." Split it into a criterion and a constraint, and make each one precise.
Criterion: the bridge holds at least 2 kg at its center for 1 minute without breaking (any number with a unit and a test is fine). Constraint: the materials cost no more than $5 (or: uses no more than 50 craft sticks). "Strong" describes success, so it becomes a criterion; "not too expensive" limits the designs, so it becomes a constraint.
Question 16 of 20 · Short Answer
A team measured wind gusts at the school flagpole at seven times: 18, 25, 31, 22, 40, 27 and 35 km/h (invented data). Write a precise criterion for a banner holder on the pole, and explain how you chose the number.
Sample criterion: the holder keeps the banner attached in gusts up to 50 km/h. The strongest measured gust was 40 km/h, so the number must be at least 40, and a margin above it covers stronger days that the seven measurements missed. Stronger wind pushes harder on a flat banner, so the largest gust, not the mean, sets the number.
Question 17 of 20 · Short Answer
A town plans a footbridge across a creek near a school. Name one impact on people and one impact on the natural environment, and write each as a precise constraint.
People: the walkway is at least 1.5 m wide with railings at least 1.1 m high, so wheelchair users and young children can cross safely. Environment: no machines or concrete enter the creek bed, and the posts stand at least 2 m from the water's edge, so fish and the creek banks are not harmed. Any constraints with a number or test and a stated reason earn credit.
Question 18 of 20 · Short Answer
A team's brief for a rain barrel at the school garden says: "Criterion: use a blue 200 L barrel." Explain what is wrong and rewrite it.
It is a solution idea, not a criterion: it picks the barrel before the problem is defined and rules out other designs. Rewrite: "Stores at least 200 L of rainwater" (a criterion), and, if color matters for a reason, a constraint such as "lets no sunlight reach the water, so algae cannot grow".
Question 19 of 20 · Short Answer
A team designing a sunshade for the playground sandbox writes: "The shade must cover the sandbox at noon." Use the fact that the sun moves across the sky during the day to explain why this criterion is not good enough, and rewrite it.
As the sun moves, shadows move and change length, so a shade that covers the sandbox at noon may leave it in full sun at 2 p.m., when children still play there. Rewrite: "The shadow covers the whole sandbox from 11 a.m. to 3 p.m. from May to September", checked by marking the shadow edge with chalk every hour on a sunny day.
Question 20 of 20 · Short Answer
A class wants a cart to carry returned library books on Fridays. There are 32 students, each returns 2 books, and a book has a mass of about 0.4 kg. Write a precise criterion for the cart, with a number, a unit and a test.
The cart must carry 32 × 2 = 64 books, about 64 × 0.4 = 25.6 kg. Criterion: "The cart carries 64 books (about 26 kg) from the classroom to the library without tipping, tested by loading it with 26 kg of books and pushing it down the hall."
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does MS-ETS1-1 mean?
MS-ETS1-1 asks students to define a design problem precisely: what a successful solution must do (criteria) and what limits it must respect (constraints). The definition must use relevant science and consider effects on people and the natural environment. The code means Middle School, Engineering, Technology and Applications of Science, core idea 1 (Engineering Design), performance expectation 1.
What grade is MS-ETS1-1 taught in?
It is a grades 6-8 standard, and schools usually spread it across all three years. Teachers often attach it to a design project in a science unit, such as the thermal energy or chemical reaction design standards (MS-PS3-3, MS-PS1-6), so students define the problem before they build.
What is the difference between criteria and constraints?
Criteria say what a solution must achieve to succeed; constraints are limits that rule some solutions out. "Lifts 500 g to a height of 1 m" is a criterion. "Costs less than $10" and "uses only cardboard and tape" are constraints. Some requirements could be phrased either way; what matters is that each one is precise and that the team agrees on it.
What does "sufficient precision" mean in MS-ETS1-1?
It means each requirement is clear enough that anyone could check whether a design meets it. Usually that means a number with a unit, or a yes-or-no test. "Strong" is not precise; "holds 3 kg for one minute" is. Words like enough, cheap, easy and well are clues that a requirement still needs a number.
Does MS-ETS1-1 have a clarification statement or an assessment boundary?
No. NGSS gives neither one for MS-ETS1-1, so lessons follow the performance expectation itself: define criteria and constraints precisely, use relevant scientific principles, and consider impacts on people and the natural environment. Building and testing a solution belong to the other middle school engineering standards.
What counts as a relevant scientific principle?
Any science idea that predicts how the solution or its surroundings will behave, such as evaporation, gravity and weight, friction, or the way shadows move with the sun. A principle is relevant when it changes a requirement: for example, knowing that warm air speeds up evaporation can make a team raise the amount of water a design must store.
Why do students need to think about impacts on people and the environment?
Because a design that meets its goal can still cause harm, and the standard asks students to find those limits before designing. Thinking early about who uses a solution, who lives nearby, and which plants, animals, water and soil it touches turns possible harm into constraints the design must respect.
Is a solution idea the same as a criterion?
No. A solution idea picks how to solve the problem, such as "use a pulley" or "make it out of wood"; a criterion says what any solution must achieve. Writing solution ideas into the problem definition rules out other designs before anyone has compared them. A good test: if a requirement names a part or material without a reason, it is probably a solution idea.
How is MS-ETS1-1 different from HS-ETS1-1?
MS-ETS1-1 asks students to define a design problem, often a local one such as a classroom or schoolyard device. HS-ETS1-1 starts from a major global challenge, such as clean water or food security, and asks students to specify qualitative and quantitative criteria and constraints that account for societal needs and wants.
How does MS-ETS1-1 connect to other engineering standards?
It is the first step of the middle school design sequence. MS-ETS1-2 evaluates competing solutions against the criteria and constraints defined here, MS-ETS1-3 analyzes test data to combine the best features, and MS-ETS1-4 uses models to test and improve a design. It builds on 3-5-ETS1-1 and leads to HS-ETS1-1.
07
Related Standards
5 standards
These standards connect to MS-ETS1-1: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
3-5-ETS1-1Prerequisite
Define a simple design problem with criteria for success and constraints on materials, time or cost
Lesson coming soon
Alongside
MS-ETS1-2Parallel
Evaluate competing design solutions systematically against the criteria and constraints
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