English · Ages 8–10
Start with the property
A mixture contains two or more substances. Ask: What property differs? Size suggests a sieve; magnetic response suggests a magnet; an insoluble solid may settle or be filtered; a dissolved solid may remain after evaporation.
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Grouped contents
5–8
1/12
Start with the property
A mixture contains two or more substances. Ask: What property differs? Size suggests a sieve; magnetic response suggests a magnet; an insoluble solid may settle or be filtered; a dissolved solid may remain after evaporation.
Correction: “I cannot see salt grains” is an observation. “The salt disappeared, so the water is pure” is unsupported. Salt dissolved; the clear solution is still a mixture.
Use clean classroom materials. Never taste samples. Children do not heat solutions; an adult controls evaporation demonstrations.
- Observe without tasting.
- Name the property difference.
- Choose a method that uses it.
- Check what passed and remained.
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Four-language word map
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Words 1–5: mixture parts
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Words 6–10: solutions
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Words 11–15: tools and changes
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Words 16–20: evidence
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Investigation: What property differs?
Predict, then match method to property. No tasting or heating.
| Sample | Difference | Method | Evidence |
|---|---|---|---|
| Large + small beads | Particle size | Sieve | Two groups |
| Iron clips + plastic | Magnetic response | Magnet | Clips attracted |
| Sand + water | Insolubility | Settle, decant or filter | Sand separate |
| Salt + water | Solubility | Adult-controlled evaporation | Salt may remain |
| Observation | Inference | Limit |
|---|---|---|
| No salt grains visible | Salt may be dissolved | Clear is not always pure |
| Sand on filter | Particles did not pass pores | Model is not to scale |
| Magnet lifts clips | Clips contain attracted material | Not every metal is attracted |
One story, four languages
English: Mira used size, magnetism, insolubility and solubility to choose four methods.
中文：米拉利用大小、磁性、不溶性和溶解性选择了四种方法。
हिन्दी: मीरा ने आकार, चुंबकत्व, अघुलनशीलता और घुलनशीलता से चार तरीके चुने।
Русский: Мира выбрала четыре способа по размеру, магнетизму, нерастворимости и растворимости.
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Ten questions and checking guide
- Which word means two or more substances together?
- Which tool separates beads by size?
- Which tool attracts iron?
- Why is salt water still a mixture?
- Can a filter recover dissolved salt?
- What remains on filter paper?
- What does decant mean?
- What changes in evaporation?
- Why is a particle drawing a model?
- What question guides method choice?
Checking guide
- mixture
- sieve
- magnet
- Salt remains as spread-out particles.
- No; dissolved particles pass with water.
- residue
- Pour off upper liquid after settling.
- Liquid becomes gas at its surface.
- It is symbolic, not real scale.
- What property differs?
A strong answer names property, method and evidence.
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Seven-day plan
| Day | Focus |
|---|---|
| 1 | Words 1–5: parts |
| 2 | Words 6–10: solution model |
| 3 | Words 11–15: tools |
| 4 | Words 16–20: evidence |
| 5 | Retell investigation |
| 6 | Answer ten questions |
| 7 | Teach five words in another edition |
10/12
Common errors and repairs
- “It disappeared.”
- It dissolved; particles spread through solvent.
- “Clear means pure.”
- A clear solution may contain solute.
- “Filter removes salt.”
- Dissolved salt passes with water.
- “Magnet attracts every metal.”
- Test first; not every metal is attracted.
- “One method works for all.”
- Choose by property; some need steps.
- “Model shows real size.”
- Particle models are not to scale.
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Transfer to new mixtures
| New mixture | Difference | Method | Check |
|---|---|---|---|
| Rice + flour | Size | Sieve | Check hole size |
| Steel + wood | Magnetism | Magnet | Test attraction |
| Chalk + water | Insolubility | Settle or filter | No tasting |
| Sugar + water | Solubility | Adult evaporation | No child heating |
A three-part mixture may need a sequence: magnet first, then size or solubility.
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FAQs, sources and onward learning
FAQ
Is clear always pure?
No; it may be a solution.
Does dissolving mean disappearing?
No; particles remain.
Can one method separate every mixture?
No; choose by property.
What does a sieve use?
Particle-size differences.
What does a filter use?
Pores trap some insoluble particles.
What does a magnet use?
Magnetic response.
Does simple evaporation recover solvent?
No; recovery needs condensation.
Why use the same comparison criteria?
It makes evidence fairer.
Sources
- American Chemical Society: Using Dissolving to Identify an Unknown
- American Chemical Society: Why Does Water Dissolve Salt?
- USGS: Evaporation and the Water Cycle
- Royal Society of Chemistry: Separating Sand and Salt
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