You will learn
- Define dissolve, solute and solvent.
- Sort soluble and insoluble.
- Plan a fair test of speed.
- Recover dissolved solid by evaporation.
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
- Soluble materials dissolve.
- Insoluble materials do not.
- Warm water and stirring speed dissolving.
- Dissolved solids can be recovered by evaporation.
Words to know
to mix completely into a liquid
the substance that dissolves
the liquid that does the dissolving
the mixture of solute and solvent
1. Discover: The sweet tea
Mawuli stirs sugar into his tea. The sugar disappears but the tea tastes sweet. “The sugar dissolved,” says his aunt. “It is still there, in tiny pieces among the water.” Sand poured into water stays on the bottom. “Sand is insoluble,” says Mawuli.
Think: How could we get the sugar back?
2. Understand: Dissolving
Idea 1: Solutions
When a solute such as sugar dissolves in a solvent such as water, the particles spread out and mix to make a solution. A solution is clear.
Idea 2: Soluble or insoluble
Sugar and salt are soluble. Sand, flour and chalk are insoluble: they stay as solid pieces and can be filtered.
Idea 3: Faster and recovery
Warm water and stirring speed up dissolving. To get the solute back, evaporate the water: the sugar or salt crystals remain.
3. Worked examples
Example 1 (I show you): Sort
Salt.
- Dissolves.
- Clear.
- Soluble.
Answer: Salt is soluble.
Example 2 (We do it together): Sort
Sand.
- Stays.
- Settles.
- Insoluble.
Answer: Sand is insoluble.
Example 3 (You try): Recover
Salt water.
Show the steps and answer
- Evaporate.
- Crystals.
- Salt back.
Answer: Evaporate to get salt.
Did you know?
Sea water has about 35 grams of dissolved salts in every litre.
Why this matters
Dissolving is used in cooking, cleaning, medicine and making salt.
4. Explore: Dissolving test
Test how temperature and stirring change dissolving time of sugar.
- Pour equal cool and warm water.
- Add equal sugar.
- Stir one and not the other.
- Time dissolving.
Think about it: what did you notice?
What did you notice? Warm and stirred sugar dissolved fastest.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- To ___ is to mix completely into a liquid.
- The ___ is what dissolves.
- The ___ is the liquid.
- A ___ is the mixture.
Guided practice
Question 1. What is dissolve?
Mix completely.
Question 2. What is a solute?
What dissolves.
Question 3. What is a solvent?
The liquid.
Independent practice
Level 1: Start
- What is dissolve?
- What is a solute?
- What is a solvent?
- Name soluble.
- Name insoluble.
Level 2: Grow
- Why stir?
- Why warm water?
- Why filter sand?
Level 3: Stretch
- Sort materials.
- Time dissolving.
- Recover salt.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Explain how to get salt from sea water.
Show a sample answer
Steps.
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: It is still there.
Fix: Some do not.
8. Lesson summary and revision card
- I can define dissolve, solute and solvent.
- I can sort soluble and insoluble.
- I can plan a fair test of speed.
- I can recover dissolved solid by evaporation.
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
- Soluble materials dissolve.
- Insoluble materials do not.
- Warm water and stirring speed dissolving.
- Dissolved solids can be recovered by evaporation.
11. Next lesson
Next lesson: Reversible changes. 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 dissolve, solute, solvent. [3 marks]
- Describe a fair test on dissolving speed. [3 marks]
- Explain how to recover a solute. [2 marks]
- Safety rules. [2 marks]
Total: 10 marks.
Marking guide and model answers
- 1 each
- Equal amounts [1]; change one thing [1]; time [1]
- Evaporate [1]; crystals remain [1]
- 1 each
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 dissolve?
- What is a solute?
- What is a solvent?
- Name soluble.
- Name insoluble.
- Why stir?
- Why warm water?
- Why filter sand?
- Sort materials.
- Time dissolving.
Homework
Test what dissolves in water at home with five materials.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is dissolve? | Mix completely. | 1 |
| 2. What is a solute? | What dissolves. | 1 |
| 3. What is a solvent? | The liquid. | 1 |
| 4. Name soluble. | Salt. | 1 |
| 5. Name insoluble. | Sand. | 1 |
| 6. Why stir? | Faster. | 1 |
| 7. Why warm water? | Particles move. | 1 |
| 8. Why filter sand? | Insoluble. | 1 |
| 9. Sort materials. | Table. | 1 |
| 10. Time dissolving. | Table. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Mix completely.; 2 What dissolves.; 3 The liquid.; 4 Salt.; 5 Sand.. Level 2: 1 Faster.; 2 Particles move.; 3 Insoluble.. Level 3: 1 Table.; 2 Table.; 3 Steps..
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 dissolve, solute and solvent | 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 Sort soluble and insoluble | 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 Plan a fair test of speed | 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 Recover dissolved solid by evaporation | 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: “The sugar disappeared forever.” It is still there.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Explain dissolving.
- 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 tests dissolving. You do not need to be an expert to help.
- Stir sugar into tea.
- Ask “Can we get it back?”
- Use warm water only.
- 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 dissolve, solute and solvent; sort soluble and insoluble; plan a fair test of speed; recover dissolved solid by evaporation.
Prerequisite knowledge. Grade 3 matter ideas: solids, liquids, gases, heating and cooling, melting, freezing and evaporation.
Materials. Cups, spoons, salt, sugar, sand. 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. Gather samples.
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). Stir sugar into tea and ask, “Where did it go?”
Explanation (10 min). Teach dissolving.
Guided activity (10 min). Learners test.
Independent activity (10 min). Learners recover.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. Soluble? How fast?
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. “The sugar disappeared forever.” It is still there.
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 dissolving. 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 9, topic 8; Next Generation Science Standards, structure and properties of matter; Cambridge Primary Science Stage 4, chemistry: states of matter and materials; IB Primary Years Programme, how the world works. These sources informed the lesson.