You will learn
- Define gravity.
- Distinguish mass and weight.
- Calculate weight.
- Compare worlds.
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
- Mass is in kilograms; weight in newtons.
- Weight = mass × g.
- g is about 10 N/kg on Earth.
- Weight changes on other worlds; mass does not.
Words to know
the force pulling masses together
the force of gravity on a mass
the amount of matter
the force per kilogram, g
1. Discover: The astronaut’s scale
An astronaut with a mass of 60 kg weighs about 600 N on Earth but only about 100 N on the Moon. “Her mass has not changed,” says Mr Dankwa. “The Moon’s pull is weaker.”
Think: What would she weigh in space far from any planet?
2. Understand: Gravity
Idea 1: Gravity
Gravity pulls all masses together. Earth’s large mass gives a strong pull towards its centre.
Idea 2: Weight
Weight is the gravitational force on a mass, measured in newtons. Weight = mass × gravitational field strength (g). On Earth, g is about 10 N/kg (9.8 exactly).
Idea 3: Other worlds
Mass stays the same everywhere. Weight depends on g: about 1.6 N/kg on the Moon and 3.7 N/kg on Mars.
3. Worked examples
Example 1 (I show you): Calculate
Weight.
- Mass 5 kg.
- g = 10.
- 50 N.
Answer: W = 50 N.
Example 2 (We do it together): Compare
Moon.
- g = 1.6.
- 5 kg.
- 8 N.
Answer: Lighter.
Example 3 (You try): Explain
Mass vs weight.
Did you know?
On Jupiter, g is about 25 N/kg, so a person would weigh about two and a half times as much as on Earth.
Why this matters
Gravity shapes orbits, tides and how we move.
4. Explore: Weight table
Hang masses of 100 g to 500 g on a newton meter and compare readings with predictions using W = m × g (with g = 10 N/kg).
- Convert grams to kg.
- Predict.
- Measure.
- Compare.
Think about it: what did you notice?
What did you notice? Measurements matched predictions closely.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- ___ is the force pulling masses together.
- ___ is the force of gravity on a mass.
- ___ is the amount of matter.
- ___ field strength is the force per kilogram.
Guided practice
Question 1. What is gravity?
Pull.
Question 2. What is weight?
Gravity force.
Question 3. What unit?
Newton.
Independent practice
Level 1: Start
- What is gravity?
- What is weight?
- What unit?
- g on Earth?
- g on Moon?
Level 2: Grow
- Why differs?
- Why mass same?
- Why newtons?
Level 3: Stretch
- Predict.
- Measure.
- Compare.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Explain the difference between mass and weight.
Show a sample answer
Use the Moon.
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: Different.
Fix: Weaker with distance.
8. Lesson summary and revision card
- I can define gravity.
- I can distinguish mass and weight.
- I can calculate weight.
- I can compare worlds.
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
- Mass is in kilograms; weight in newtons.
- Weight = mass × g.
- g is about 10 N/kg on Earth.
- Weight changes on other worlds; mass does not.
11. Next lesson
Next lesson: Friction. 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 gravity and weight. [2 marks]
- Calculate weight of 8 kg on Earth. [2 marks]
- Explain why weight changes on the Moon. [4 marks]
- Safety rule. [2 marks]
Total: 10 marks.
Marking guide and model answers
- 1 each
- Formula [1]; 80 N [1]
- Different g [1]; weaker pull [1]; mass same [1]; lighter [1]
- 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 gravity?
- What is weight?
- What unit?
- g on Earth?
- g on Moon?
- Why differs?
- Why mass same?
- Why newtons?
- Predict.
- Measure.
Homework
Calculate your weight on Earth and the Moon.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is gravity? | Pull. | 1 |
| 2. What is weight? | Gravity force. | 1 |
| 3. What unit? | Newton. | 1 |
| 4. g on Earth? | 10 N/kg. | 1 |
| 5. g on Moon? | 1.6 N/kg. | 1 |
| 6. Why differs? | Different pull. | 1 |
| 7. Why mass same? | Matter constant. | 1 |
| 8. Why newtons? | Force. | 1 |
| 9. Predict. | Numbers. | 1 |
| 10. Measure. | Table. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Pull.; 2 Gravity force.; 3 Newton.; 4 10 N/kg.; 5 1.6 N/kg.. Level 2: 1 Different pull.; 2 Matter constant.; 3 Force.. Level 3: 1 Numbers.; 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 gravity | 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 Distinguish mass and weight | 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 Calculate weight | 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 Compare worlds | 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: “Mass and weight are the same.” Different.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Calculate weight.
- 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 studies gravity and weight. You do not need to be an expert to help.
- Weigh things at home.
- Ask “Mass or weight?”
- Keep it fun.
- 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 gravity; distinguish mass and weight; calculate weight; compare worlds.
Prerequisite knowledge. Grade 5 ideas: pushes, pulls, gravity, friction and air resistance.
Materials. Newton meters, masses. 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. Check meters.
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). Drop a ball and ask, “Why does it fall?”
Explanation (10 min). Teach gravity.
Guided activity (10 min). Learners measure.
Independent activity (10 min). Learners calculate.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. Mass or weight? Which unit?
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. “Mass and weight are the same.” Different.
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. Calculate weight. 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 6 Unit 6, topic 4; Next Generation Science Standards, forces and interactions; Cambridge Lower Secondary Science, physics; IB Primary Years Programme, how the world works. These sources informed the lesson.