Notes For All Chapters – English Class 6
1. Introduction
- Glass is a beautiful and useful material.
- It is used to make many everyday things like:
- Light bulbs
- Bottles and jars
- Glasses (for drinking and reading)
- Windowpanes
- Marbles
- Glass is a man-made material.
2. What is Glass Made From?
- Glass is made from sand!
- Clean white sand is mixed with chemicals like:
- Soda (sodium carbonate)
- Lime (calcium carbonate)
- This mixture is heated in a furnace until it melts into a hot liquid.
- When cooled, it becomes hard and stiff.
3. How is Glass Shaped?
- Once glass cools down, it becomes brittle (breaks easily) and cannot be shaped.
- So, glass must be shaped while it is still hot and soft.
- Methods of shaping glass:
- Pouring into molds to make bottles, bulbs, and other objects.
- Rolling it into flat sheets for windows.
- Blowing it into different shapes.
- Floating it on molten metal to make very smooth glass sheets.
- Drawing it into thin fibers to make glass wool.
4. Properties of Glass
Glass has many useful properties:
Transparent – We can see through it.
Strong and Hard – It can hold weight.
Impermeable – It does not allow water or liquids to pass through.
Safe for Food – It does not change the taste or smell of stored food.
Smooth Surface – It can be cleaned easily.
Beautiful Appearance – It is used for decoration.
5. Colored Glass
- Normal glass is colorless, but it can be made colored by adding special chemicals.
- Some colors of glass:
- Blue, Violet, Green, Red, Yellow, Pink, Orange, Black, White
- Colored glass is used to make stained glass windows, especially in churches and decorative art.
6. Recycling Glass
- Glass can be 100% recycled.
- Old glass can be melted and used to make new glass.
- Benefits of recycling glass:
- Saves energy – Recycling one glass bottle can save enough energy to power a TV for 20 minutes!
- Cheaper than making new glass.
- Better for the environment.
- So, we should always handle glass carefully and recycle it whenever possible.
7. Important Vocabulary
- Furnace – A very hot oven used to melt materials.
- Brittle – Something that breaks easily.
- Transparent – Something we can see through.
- Impermeable – Something that does not allow liquids to pass through.
- Mold – A shape in which liquid material is poured to make objects.
- Stained Glass – Colored glass used for decoration.
- Recycling – Reusing old materials to make new things.
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