The History of Glass
The very first glass, known to stone age people which was used for making weapons and decorative objects, was obsidian, black volcanic glass. The earliest known man made glass dates back to around 3500BC, with finds in Egypt and Eastern Mesopotamia. The discovery of glassblowing around 1st century BC was a major breakthrough in glass making.
What is Glass Made From?
Glass is made from common raw materials – sand, limestone and soda ash. Soda ash is sodium carbonate, a natural grey/white powder; limestone and sand are also natural and common materials. Each is taken out of the ground from quarries. It is a very energy intensive process.
What Can Glass Be Recycled into?
- New bottles and jars
- Made into Glassphalt – to resurface roads
- For creating and repairing the surfaces on golf courses and sports pitches, cemeteries, and as decorative mulch.
- In swimming pool or spa filtration systems
The great thing about glass is that it can be recycled over and over and over again.
Recycling one glass bottle creates 20% less air pollution and 50% less water pollution than making a new bottle from raw materials.
The energy saved from recycling a single bottle will power a 100 watt light bulb for almost an hour, or a colour TV for 20 minutes.
The UK currently Recycles around 50% of glass containers.
Some countries like Finland and Switzerland recycle almost 90% of their glass.
Activities in the classroom
- Talk about how glass jars and bottles could be re-used at home e.g. for jam making, pickling or home made cordials.
- Get the class or school to collect unwanted jars and decorate them to sell as a school fundraiser – perhaps as outdoor lanterns, snowdomes, mini greenhouse, terrariums.
- Discuss as a class what the advantages and disadvantages are of using glass containers as opposed to other containers for instance made from plastic.
- Talk about how glass is made and its history.
TOCK would love to hear about how, as part of the TOCK Team, children are helping to ‘SAVE THE EARTH’. Let him know what you have been doing individually or as a school and he can share it on the website for the rest of the TOCK team to see.