You will learn
- Define variable.
- Identify the independent variable.
- Identify the dependent variable.
- List controlled variables.
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 variable is something that can change.
- We change one variable.
- We measure the result.
- We keep everything else the same.
Words to know
anything that can change in an investigation
the one thing we change
the thing we measure
a thing we keep the same
1. Discover: The bouncing balls
Kojo wants to know if the height a ball is dropped from changes how high it bounces. He drops the same ball from 50 cm, 100 cm and 150 cm onto the same floor and measures each bounce. “Height is what I change,” he says. “Bounce height is what I measure. The ball and floor stay the same.”
Think: What would go wrong if he used a different ball each time?
2. Understand: Variables
Idea 1: Independent variable
The independent variable is the one thing we choose to change on purpose, such as drop height.
Idea 2: Dependent variable
The dependent variable is what we measure to see the effect, such as bounce height. It depends on the change we made.
Idea 3: Controlled variables
Controlled variables stay the same: the ball, the floor and how we measure. Controlling them makes the test fair. Every variable that might matter needs a decision.
3. Worked examples
Example 1 (I show you): Identify
Plant growth with different water amounts.
- What do we change?
- What do we measure?
- What stays the same?
Answer: Change water; measure height; keep light and soil the same.
Example 2 (We do it together): Identify
Ball drop from different heights.
- Change: height.
- Measure: bounce.
- Same: ball, floor.
Answer: Independent is height; dependent is bounce.
Example 3 (You try): Try
Paper plane wing length and distance.
Show the steps and answer
- What changes?
- What is measured?
- What stays the same?
Answer: Change wing length; measure distance; keep paper and launch the same.
Did you know?
Medical studies use controlled variables too, so that only one thing differs between the groups being compared.
Why this matters
Knowing the variables stops us blaming the wrong cause for a result.
4. Explore: Variable detectives
Identify the three kinds of variables in three investigations.
- Read each scenario.
- Underline what changes.
- Circle what is measured.
- List what stays the same.
Think about it: what did you notice?
What did you notice? Every fair test had one change and several controls.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- The ___ variable is the one we change.
- The ___ variable is what we measure.
- A ___ variable is kept the same.
- A ___ is anything that can change.
Guided practice
Question 1. What is a variable?
Can change.
Question 2. What do we change?
Independent.
Question 3. What do we measure?
Dependent.
Independent practice
Level 1: Start
- What is a variable?
- What do we change?
- What do we measure?
- What stays the same?
- How many do we change?
Level 2: Grow
- Why change only one?
- Why control others?
- Why measure?
Level 3: Stretch
- Name variables in a test.
- Drop a ball and measure.
- Explain the controls.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Name the variables in a plant test.
Show a sample answer
Three kinds.
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: Change one.
Fix: It is what we measure.
8. Lesson summary and revision card
- I can define variable.
- I can identify the independent variable.
- I can identify the dependent variable.
- I can list controlled variables.
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 variable is something that can change.
- We change one variable.
- We measure the result.
- We keep everything else the same.
11. Next lesson
Next lesson: Fair testing. 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 independent and dependent variable. [2 marks]
- Identify the three variables in a ball bounce test. [3 marks]
- Why control variables? [2 marks]
- List two controlled variables. [2 marks]
- Safety rule? [1 mark]
Total: 10 marks.
Marking guide and model answers
- Independent: what we change [1]; dependent: what we measure [1]
- Change [1]; measure [1]; control [1]
- Fair test [1]; know the cause [1]
- 1 each
- Any [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 variable?
- What do we change?
- What do we measure?
- What stays the same?
- How many do we change?
- Why change only one?
- Why control others?
- Why measure?
- Name variables in a test.
- Drop a ball and measure.
Homework
Think of a test at home. Name what you change, measure and keep the same.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is a variable? | Can change. | 1 |
| 2. What do we change? | Independent. | 1 |
| 3. What do we measure? | Dependent. | 1 |
| 4. What stays the same? | Controlled. | 1 |
| 5. How many do we change? | One. | 1 |
| 6. Why change only one? | Fair test. | 1 |
| 7. Why control others? | Know the cause. | 1 |
| 8. Why measure? | Evidence. | 1 |
| 9. Name variables in a test. | List. | 1 |
| 10. Drop a ball and measure. | Table. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Can change.; 2 Independent.; 3 Dependent.; 4 Controlled.; 5 One.. Level 2: 1 Fair test.; 2 Know the cause.; 3 Evidence.. Level 3: 1 List.; 2 Table.; 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 variable | 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 Identify the independent variable | 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 Identify the dependent variable | 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 List controlled variables | 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: “Change everything to get better results.” Change one.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Name independent, dependent and controlled variables.
- 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 learns about variables. You do not need to be an expert to help.
- Name variables in a cooking test.
- Ask “What stays the same?”
- Use safe items.
- 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 variable; identify the independent variable; identify the dependent variable; list controlled variables.
Prerequisite knowledge. Grade 3 inquiry ideas: asking questions, predictions, fair tests, measuring, tables and simple conclusions.
Materials. Soft ball, metre rule, notebooks. 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. Mark heights on a wall.
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). Ask, “How do we make a test fair?”
Explanation (10 min). Teach the three variables.
Guided activity (10 min). Learners identify them.
Independent activity (10 min). Learners share.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. What changes? What is measured? What stays the same?
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. “Change everything to get better results.” Change one.
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. Name independent, dependent and controlled variables. 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 4 Unit 1, topic 4; Next Generation Science Standards, planning and carrying out investigations; Cambridge Primary Science Stage 4, thinking and working scientifically; IB Primary Years Programme, how we express ourselves and how the world works. These sources informed the lesson.