You will learn
- Define a problem.
- State criteria.
- State constraints.
- Identify the user.
Version 0.2 · expanded edition · built from cited public sources Content is based on the official frameworks and sources listed under Sources and standards. No official endorsement is claimed. Written in the style of common primary school assessments. No exam result is promised.
Student lesson
- A clear problem statement guides the design.
- Criteria say what success looks like.
- Constraints are limits.
- Designs should serve users.
Words to know
something that needs a solution
what a good solution must do
a limit such as time or cost
the person who will use a design
1. Discover: The muddy path
After rain the school path floods and children arrive with muddy shoes. Ama writes: “Children need a dry way to walk from the gate to the classroom.” Her group lists criteria and constraints before sketching anything.
Think: Why is it better to define the problem before choosing a solution?
2. Understand: Defining problems
Idea 1: Statement
A good problem statement says who needs what: “Children need a dry way to walk from the gate to the classroom.” It does not name the solution.
Idea 2: Criteria
Criteria measure success: stays dry, lasts a year, safe for all children.
Idea 3: Constraints
A constraint is a limit: low cost, local materials, two weeks to build.
3. Worked examples
Example 1 (I show you): Write
Problem statement.
- Who.
- Needs what.
- No solution.
Answer: Children need a dry path.
Example 2 (We do it together): List
Criteria.
- Dry.
- Safe.
- Durable.
Answer: Three criteria.
Example 3 (You try): List
Constraints.
Show the steps and answer
- Cost.
- Time.
- Materials.
Answer: Three constraints.
Did you know?
Many successful inventions began as someone noticing an everyday annoyance.
Why this matters
Defining the right problem saves time and avoids useless designs.
4. Explore: Problem cards
Choose a school problem, write a problem statement, three criteria and two constraints on a card, and swap with a partner for feedback.
- Choose a problem.
- Write the statement.
- Add criteria.
- Add constraints.
Think about it: what did you notice?
What did you notice? Partners found unclear words.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- A ___ needs a solution.
- ___ say what a good solution must do.
- A ___ is a limit.
- The ___ will use the design.
Guided practice
Question 1. What is a problem?
Needs solving.
Question 2. What are criteria?
Success measures.
Question 3. What is a constraint?
Limit.
Independent practice
Level 1: Start
- What is a problem?
- What are criteria?
- What is a constraint?
- Who is the user?
- Name a constraint.
Level 2: Grow
- Why define?
- Why criteria?
- Why users?
Level 3: Stretch
- Write a statement.
- List criteria.
- Explain.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Explain the difference between criteria and constraints.
Show a sample answer
Give examples.
Another one. Tell a family member one thing from this lesson. Use the words you learned.
Show a sample answer
A clear sentence that uses at least one word from Words to know.
7. Common mistakes
Fix: No.
Fix: They limit designs.
8. Lesson summary and revision card
- I can define a problem.
- I can state criteria.
- I can state constraints.
- I can identify the user.
9. Check and master
Answer all 14 questions. You will see feedback after each one.
Your result appears here after you answer every question.
10. Key takeaways
- A clear problem statement guides the design.
- Criteria say what success looks like.
- Constraints are limits.
- Designs should serve users.
11. Next lesson
Next lesson: Researching solutions. Keep going with the next idea in this course.
Exam practice
These questions are written in the style of common school and international primary assessments. Try them on your own, without looking back. Then check your answers in the marking guide. The marks are shown in brackets.
- Define criteria and constraint. [2 marks]
- Write a problem statement. [3 marks]
- List two criteria and two constraints. [3 marks]
- Safety rule. [2 marks]
Total: 10 marks.
Marking guide and model answers
- 1 each
- User [1]; need [1]; no solution [1]
- Any four [3 marks: 1 per pair, 1 for clarity]
- Any [1]; reason [1]
Score guide: 9 to 10 = secure. 6 to 8 = nearly there, revise the parts you missed. Under 6 = work through the lesson again with a grown-up.
Printable worksheet
- What is a problem?
- What are criteria?
- What is a constraint?
- Who is the user?
- Name a constraint.
- Why define?
- Why criteria?
- Why users?
- Write a statement.
- List criteria.
Homework
Write a problem statement for something at home.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is a problem? | Needs solving. | 1 |
| 2. What are criteria? | Success measures. | 1 |
| 3. What is a constraint? | Limit. | 1 |
| 4. Who is the user? | The person using it. | 1 |
| 5. Name a constraint. | Cost. | 1 |
| 6. Why define? | Aim better. | 1 |
| 7. Why criteria? | Judge designs. | 1 |
| 8. Why users? | They decide use. | 1 |
| 9. Write a statement. | Card. | 1 |
| 10. List criteria. | List. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Needs solving.; 2 Success measures.; 3 Limit.; 4 The person using it.; 5 Cost.. Level 2: 1 Aim better.; 2 Judge designs.; 3 They decide use.. Level 3: 1 Card.; 2 List.; 3 Sentence..
Quiz answers: 1 B, 2 C, 3 A, 4 B, 5 C, 6 A, 7 B, 8 C, 9 A, 10 B, 11 C, 12 A, Challenge 1 B, Challenge 2 C.
Mastery and remediation
| Objective | Bronze (Developing) | Silver (Proficient) | Gold (Advanced) |
|---|---|---|---|
| O1 Define a problem | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O2 State criteria | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O3 State constraints | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O4 Identify the user | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
Courseversity badge thresholds (overall quiz score): Gold = 90–100%; Silver = 80–89.9%; Bronze = 70–79.9%. A badge is never a full record of progress.
If a learner struggles
- Find the misconception: “A problem statement includes the solution.” No.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Define a problem with criteria and constraints.
- Guided practice: work through one example together and let the learner try the next one.
- Reassess: use the quiz again or the worksheet.
- Move on when the learner shows Silver-level evidence independently.
For parents and guardians
In this lesson your child defines a problem. You do not need to be an expert to help.
- Notice a problem.
- Ask “Who needs it solved?”
- Listen.
- Ask “how do you know?” after each answer, and listen.
- Praise effort, not only right answers. Mistakes are how we learn.
- Ten to fifteen minutes a day is better than one long session.
Teacher package
1–5. Objectives, prerequisites, materials, preparation, duration
Lesson objectives. Learners will: define a problem; state criteria; state constraints; identify the user.
Prerequisite knowledge. Grade 4 ideas: testing fairly, improving a design and using simple technology.
Materials. Cards, pencils. Low-resource options: use chalk or charcoal on a board or wall, drawings in the sand, and objects from the classroom instead of printed materials.
Preparation. Prepare problem cards.
Suggested duration. 45–60 minutes. It can be split into two shorter sessions.
6–9. Teaching procedure, explanation notes, guided and independent activities
Introduction (5 min). Tell a short story of a problem and ask, “What is the real problem?”
Explanation (10 min). Teach problem definition.
Guided activity (10 min). Learners write.
Independent activity (10 min). Learners swap.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. Who is the user? What are the limits?
Teacher explanation notes. Start with real objects and safe, hands-on observation. Then talk about what was seen, then draw and write. Always say “how do you know?”. Keep to the safety notes, and use local, safe materials.
10–12. Differentiation, formative assessment, common misconceptions
Support. Use real objects and pictures, short sentences and a partner. Let learners point, show or draw instead of writing. Extension. Ask learners to find a new example at home and explain how they know.
Formative assessment. Listen to learners read and explain, ask “how do you know?”, and check the independent work.
Misconceptions. “A problem statement includes the solution.” No.
13–15. Assessment questions, answer keys, marking scheme
Use the quiz, the 10-mark exam practice and the worksheet on this page. All answers and marking guides are in the answer sections above. Re-check every answer before use.
16–19. Remediation, enrichment, homework, teacher reflection
Remediation. Define a problem with criteria and constraints. Enrichment. Look for one new example near your home or school, draw it and explain it to someone. Homework. See above.
Teacher reflection. After teaching, record: which ideas learners understood; which misconceptions occurred; which activities worked; which learners need more practice; and what to improve next time.
Sources and standards
This lesson is based on the sources below, and no official endorsement is claimed. Reference starting points: Next Generation Science Standards, Cambridge Primary Science and the IB Primary Years Programme. Where a standard code is named, it points to the official framework.
Research used to shape this lesson. Courseversity Science curriculum, Grade 5 Unit 10, topic 2; Next Generation Science Standards, engineering design; Cambridge Primary Science Stage 5, thinking and working scientifically; IB Primary Years Programme, how we organise ourselves and sharing the planet. These sources informed the lesson.