You will learn
- Explain orbits.
- Link gravity to mass and distance.
- Compare weights.
- Explain satellites.
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
Words to know
a curved path around a body
the force that pulls masses together
an object that orbits a planet
the speed needed to leave a planet
1. Discover: The swinging ball
Ama swings a ball on a string in an open field. The string pulls inward, keeping the ball in a circle. “Gravity is like the string,” says her teacher. “It pulls planets toward the Sun but they keep moving sideways, so they orbit.”
Think: What if the string is cut?
2. Understand: Solar gravity
Idea 1: Orbits
A planet moves forward while the Sun’s gravity pulls it inward, so it follows a curved orbit. Without gravity it would fly off in a straight line.
Idea 2: Mass and distance
Gravity is stronger for bigger masses and weaker with distance. That is why Jupiter pulls strongly and why gravity on the Moon is about one sixth of Earth’s.
Idea 3: Satellites
A satellite stays up because it falls around Earth while moving sideways at about 28,000 km/h.
3. Worked examples
Example 1 (I show you): Predict
String cut.
- Straight line.
- No pull.
- Ball flies.
Answer: It flies off straight.
Example 2 (We do it together): Compare
Moon weight.
- One sixth.
- Less gravity.
- Lower weight.
Answer: Weight is lower.
Example 3 (You try): Explain
Satellite.
Show the steps and answer
- Falls around.
- Sideways.
- Orbit.
Answer: It falls around Earth.
Did you know?
The International Space Station orbits Earth about 16 times a day.
Why this matters
Understanding gravity helps us launch satellites and explore space.
4. Explore: Orbit model
Swing a soft ball on a string outdoors with an adult and observe what happens when speed changes and when released.
- Tie a ball to string.
- Swing slowly.
- Swing faster.
- Release (adult).
Think about it: what did you notice?
What did you notice? The faster ball needed more pull and flew straight when released.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- An ___ is a curved path.
- ___ is the pull between masses.
- A ___ orbits a planet.
- ___ velocity is the speed to leave.
Guided practice
Question 1. What holds planets in orbit?
Gravity.
Question 2. What increases gravity?
Mass.
Question 3. What reduces it?
Distance.
Independent practice
Level 1: Start
- What holds planets in orbit?
- What increases gravity?
- What reduces it?
- What is a satellite?
- Moon gravity?
Level 2: Grow
- Why orbit?
- Why Jupiter strong?
- Why satellites stay up?
Level 3: Stretch
- Run the swing.
- Compare weights.
- Explain.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Explain why planets orbit rather than fall into the Sun.
Show a sample answer
Use sideways motion.
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: They fall around.
Fix: It does.
8. Lesson summary and revision card
- I can explain orbits.
- I can link gravity to mass and distance.
- I can compare weights.
- I can explain satellites.
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
- Gravity keeps planets in orbit.
- More mass means stronger gravity.
- Closer means stronger.
- Satellites stay up by moving sideways fast.
11. Next lesson
Next lesson: Solar System models. 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 orbit and gravity. [2 marks]
- Explain why planets orbit. [3 marks]
- Compare weights. [3 marks]
- Safety rule. [2 marks]
Total: 10 marks.
Marking guide and model answers
- 1 each
- Gravity pulls [1]; sideways motion [1]; curve [1]
- Moon [1]; Jupiter [1]; reason [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 holds planets in orbit?
- What increases gravity?
- What reduces it?
- What is a satellite?
- Moon gravity?
- Why orbit?
- Why Jupiter strong?
- Why satellites stay up?
- Run the swing.
- Compare weights.
Homework
Swing a toy on a string outdoors with an adult.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What holds planets in orbit? | Gravity. | 1 |
| 2. What increases gravity? | Mass. | 1 |
| 3. What reduces it? | Distance. | 1 |
| 4. What is a satellite? | Orbiting object. | 1 |
| 5. Moon gravity? | One sixth. | 1 |
| 6. Why orbit? | Sideways motion. | 1 |
| 7. Why Jupiter strong? | Big mass. | 1 |
| 8. Why satellites stay up? | Falling around. | 1 |
| 9. Run the swing. | Notes. | 1 |
| 10. Compare weights. | Table. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Gravity.; 2 Mass.; 3 Distance.; 4 Orbiting object.; 5 One sixth.. Level 2: 1 Sideways motion.; 2 Big mass.; 3 Falling around.. Level 3: 1 Notes.; 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 Explain orbits | 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 Link gravity to mass and distance | 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 Compare weights | 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 Explain satellites | 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: “Satellites have no gravity.” They fall around.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Explain orbits.
- 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 in space. You do not need to be an expert to help.
- Throw a ball and watch.
- Ask “Why does it fall?”
- Open space.
- 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: explain orbits; link gravity to mass and distance; compare weights; explain satellites.
Prerequisite knowledge. Grade 4 ideas: the Earth, Sun and Moon, day and night, shadows and the seasons.
Materials. Ball, string. 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. Clear space.
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). Throw a ball and ask, “Why does it curve down?”
Explanation (10 min). Teach solar gravity.
Guided activity (10 min). Learners model.
Independent activity (10 min). Learners explain.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. What pulls? Why orbit?
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. “Satellites have no gravity.” They fall around.
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. Explain orbits. 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 9, topic 9; Next Generation Science Standards, Earth’s place in the universe; Cambridge Primary Science Stage 5, Earth and space; IB Primary Years Programme, where we are in place and time. These sources informed the lesson.