TEACHGYAN • CLASS 6 SCIENCE • CURIOSITY
Chapter 6 – Materials Around Us
Materials • Properties • Grouping • Solubility • Transparency • Hardness • Uses • MCQs • Worksheet
Chapter focus: Objects are made from materials with different properties. Comparing properties helps us group materials and choose suitable materials for particular uses.
🎯 Learning Goals
- Distinguish objects from the materials used to make them.
- Compare materials using observable properties.
- Group materials in different ways.
- Understand soluble and insoluble substances in water.
- Describe transparent, translucent and opaque materials.
- Relate properties to the uses of materials.
- Understand why one material can have several uses.
🪵 1. Objects and Materials
A chair is an object; wood, metal or plastic may be the material from which it is made. The same material can be used to make many different objects, and the same type of object can be made from different materials.
🔎 2. Properties of Materials
| Property | Meaning / observation |
|---|---|
| Appearance | Colour, lustre or surface look. |
| Hardness | Resistance to scratching or indentation. |
| Solubility | Whether a substance dissolves in a particular solvent such as water. |
| Transparency | How much light can pass through a material. |
| Flexibility | Ability to bend without breaking. |
| Texture | How a surface feels to touch. |
💧 3. Soluble and Insoluble Materials
Some substances dissolve in water and are called soluble in water. Salt and sugar are familiar examples. Sand and many other substances do not dissolve and are insoluble in water.
Solubility depends on the substance and solvent; “soluble” should therefore be stated with the solvent when needed.
💡 4. Transparent, Translucent and Opaque
- Transparent: lets most light pass through clearly, such as clean glass.
- Translucent: lets some light through but does not allow clear images, such as butter paper.
- Opaque: blocks light, such as wood or cardboard.
🧺 5. Grouping Materials
Materials can be grouped according to different properties. One group may be based on solubility, another on transparency, another on hardness or texture. There is not always only one correct way to group a collection.
🏠 6. Choosing Materials for Uses
We choose materials according to the properties required. A window needs a material that allows light through; a cooking vessel needs a material that can tolerate heating and is suitable for the purpose; a raincoat needs a material that resists water.
🔬 7. Simple Investigation
- Collect safe samples such as paper, wood, plastic, metal, salt and sand.
- Observe appearance and texture.
- Test suitable samples for solubility in water.
- Observe whether light passes through sheets or objects.
- Group the samples using one property.
- Try grouping them using a different property and compare.
📋 Worked Examples
Example 1 – One Object, Different Materials
A bottle may be made from glass, plastic or metal. Its use depends on required properties such as strength, weight, transparency and resistance to the contents.
Example 2 – Solubility
When salt is stirred into water, it appears to disappear because it dissolves. Sand settles because it is insoluble in water under ordinary conditions.
Example 3 – Transparency
A clean glass window is transparent, frosted glass is translucent, and a wooden door is opaque.
🧠 Think Like a Scientist
- Why can the same material be used for many different objects?
- Why is grouping useful when studying many materials?
- Can a material be classified differently using different properties? Explain.
- Why is glass suitable for a window but not usually for a hammer handle?
- Why should a solubility statement mention the solvent when necessary?
📝 Important Practice Questions
- What is a material?
- How is an object different from a material?
- Name four properties used to compare materials.
- What is solubility?
- Give two soluble substances and two insoluble substances in water.
- Differentiate transparent, translucent and opaque materials.
- Why do we group materials?
- Give two examples where a material’s property determines its use.
- Why can one object be made from different materials?
- What is flexibility?
🔥 Competency / HOTS
- You need to choose a material for a school window. Which properties would you consider and why?
- Design a table to classify five classroom objects by material and transparency.
- A substance disappears when stirred into water. Does that automatically mean it has vanished? Explain.
- Give two different ways to group the same six materials.
- Why might a material that is strong still be unsuitable for a particular object?
🧩 MCQ Practice
- Salt in water is generally — A. soluble B. opaque C. magnetic D. rough only
- Sand in water is generally — A. insoluble B. transparent C. soluble D. gaseous
- A material that allows clear light transmission is — A. transparent B. opaque C. rough D. insoluble
- Frosted glass is commonly — A. translucent B. opaque always C. soluble D. magnetic
- Wood is generally — A. opaque B. transparent C. soluble in water D. liquid
- Materials can be grouped using — A. different properties B. only colour C. only size D. no properties
- The property of bending without breaking is related to — A. flexibility B. transparency C. solubility D. lustre
- A window is commonly made from a material selected for its — A. transparency B. solubility C. food value D. magnetic pole
Answer Key: 1-A, 2-A, 3-A, 4-A, 5-A, 6-A, 7-A, 8-A
📄 Printable Worksheet
- List five objects and the materials from which they are made.
- Write four properties of materials.
- Classify five substances as soluble or insoluble in water.
- Give two examples each of transparent, translucent and opaque materials.
- Explain why grouping materials is useful.
- Choose suitable materials for a raincoat, window and cooking utensil and justify your choices.
- Group six classroom objects in two different ways.
- Explain the difference between an object and its material.
- Record three observations from a simple materials investigation.
- Write two safety precautions for classroom testing.
🔁 Quick Revision
| Concept | Remember |
|---|---|
| Material | Substance used to make an object. |
| Soluble | Dissolves in a specified solvent. |
| Transparent | Allows clear transmission of light. |
| Translucent | Allows some light through but not clear images. |
| Opaque | Does not allow light to pass through. |
| Flexibility | Ability to bend without breaking. |
✅ Mastery Checklist
- ☐ I can distinguish objects and materials.
- ☐ I can compare materials using properties.
- ☐ I can explain solubility.
- ☐ I can classify transparent, translucent and opaque materials.
- ☐ I can group materials in different ways.
- ☐ I can connect properties with uses.