What Counts, and What Limits
A 55-minute Grade 4 lesson on defining a design problem with measurable criteria and honest constraints.
What Counts, and What Limits is a free 55-minute Grade 3 to Grade 5 science lesson plan for Common Core standard 3-5-ETS1-1 — define a design problem, with what counts as success and what limits you. It is timed across 5 sections, gives the exact wording to use where the wording carries the mathematics, names 3 misconceptions with the teaching move that addresses each, and ends with an exit ticket and a printable worksheet with its answer key.
- Grade:
- Grade 3 to Grade 5
- Length:
- 55 minutes
- Standard:
- 3-5-ETS1-1
Grade 3 to Grade 5 · Engineering Design
3-5-ETS1-1
Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.
Objective
Students will be able to write criteria that can be measured and constraints that are real.
Students are successful when they can
- Writes at least two measurable criteria.
- Writes at least two real constraints.
- Rewrites a criterion nobody could check.
What you need
- A real design brief from the school grounds
- Two-column planning sheets
- The printable practice sheet linked at the end of this plan
The lesson
Warm-up
5 min- Offer the criterion 'it must work well'.
- Ask how anybody would check it.
Teach — measurable, and real
14 min- Rewrite 'work well' as 'heard from the far gate' — now it can be checked.
- Write a second: 'stands in a strong wind' becomes 'stays up in a 30 mph gust'.
- List constraints: ten pounds, two afternoons, no mains power, carried by one person.
- Say the difference: criteria are checked at the end, constraints bind you throughout.
- Test a doubtful line: 'must be attractive'. Ask whether it can be measured, and how.
- Say why constraints must be real: an imagined limit rules out good solutions for nothing.
“How would somebody check that? If they cannot, rewrite it.”
Investigate — write and swap
19 min- Groups write a brief with three criteria and three constraints.
- They swap briefs and try to score an imaginary design against another group's.
- They mark every criterion they could not check.
- They rewrite those criteria so they can be.
Independent practice
14 min- Students complete the 'What Counts, and What Limits' page.
- Check the sort is by function, not by wording.
Close
3 min- Adopt the sharpest brief for the design lessons.
What goes wrong, and why
Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.
Writes criteria that cannot be measured.
Why: They describe the goal.
Fix: Ask how you would check it. Rewrite until you can.
Invents constraints that are not real.
Why: Limits feel rigorous.
Fix: An imagined limit rules out good designs for nothing.
Confuses a solution with a criterion.
Why: 'It must be a net' sounds specific.
Fix: That is one solution. What does the net have to achieve?
If they are not there yet
- Six statements to sort.
- One criterion supplied to rewrite.
If they finish early
- Write a criterion with a number in it and one without, and compare.
- Add a safety constraint and say who it protects.
- Find a criterion that conflicts with a constraint.
Exit ticket
Rewrite 'the alarm must work well' as a criterion somebody could check.
What to look for: Something measurable, such as heard from the far gate or heard at fifty metres. A restatement with no check means the measurable point needs another run.
Printable practice for 3-5-ETS1-1
Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.
- What Counts, and What LimitsSort each one into criterion or constraint.
Questions about What Counts, and What Limits
How long does the What Counts, and What Limits lesson take?
55 minutes, split across 5 timed sections: warm-up 5 min, teach 14 min, investigate 19 min, independent practice 14 min, close 3 min. The minutes are stated per section and add up to the stated length, so the plan can be cut or extended at a section boundary rather than abandoned halfway.
Which standard does What Counts, and What Limits teach?
3-5-ETS1-1 — 3-5-ETS1-1, Engineering Design for Grade 3 to Grade 5: “Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.” In plain terms, define a design problem, with what counts as success and what limits you.
What do I need to teach this lesson?
A real design brief from the school grounds, two-column planning sheets and the printable practice sheet linked at the end of this plan. Everything listed is either ordinary classroom equipment or a free printable from this site — there is nothing to buy and nothing to prepare beyond photocopying.
What mistakes should I expect in this lesson?
Three, each a reasoning error rather than carelessness: writes criteria that cannot be measured; invents constraints that are not real and confuses a solution with a criterion. The plan gives the thinking behind each one and the teaching move that addresses the thinking rather than the symptom.
How do I know whether the lesson worked?
The exit ticket asks: “Rewrite 'the alarm must work well' as a criterion somebody could check.” Something measurable, such as heard from the far gate or heard at fifty metres. A restatement with no check means the measurable point needs another run. That tells you whether the class needs a reteach or a thirty-second conversation before you plan tomorrow.
Is there a worksheet to go with What Counts, and What Limits?
Yes — 1 printable 3-5-ETS1-1 worksheet, linked at the end of the plan and free like the rest of the site. Each one comes with an answer key and 25 versions, so the practice after the lesson can be a different paper on every desk.
Is What Counts, and What Limits free to use?
Yes. The plan, its printables and their answer keys are free to read, print and photocopy for your own class, with no account and no email capture. It was last reviewed on 8 September 2026. Please do not resell it or republish it as your own.
Last reviewed 2026-09-08. Aligned to 3-5-ETS1-1 of the Next Generation Science Standards.