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What is glass?

Glass has been around for a very long time; archeologists have found beads covered in glass from 4,000BC. In 2,000BC the Egyptians made glass bottles we would recognise and the romans brought glass making to Britain.

Glass is made from silica sand, sodium carbonate and limestone which is heated to 1700°C until it melts to form a liquid; when this liquid cools, glass is formed.

Wow fact: Glass is actually a firm liquid so if is left long enough it slumps; this is why some windows in very old houses are wobbly.

Many other chemicals can be added depending on the properties required for the glass i.e. boron oxide is added to make Pyrex glass. Its ability to strengthen the structure of glass and protect it from thermal expansion and cracking makes it perfect for the production of kitchen cookware.

Different types of glass should not be recycled together as they can produce structural weaknesses and the new products could explode or crack when people try to use them. This is why at recycling centres people are asked to put different types of glass in different places i.e. bottles/ jars into a special bottle bank and window planes and Pyrex dishes go elsewhere.

How is glass recycled? 

Watch a video on how glass is recycled, or see images of the stages in this process

Bottles and jars are the most common and easiest type of glass to recycle; these are usually collected by councils from homes or bottle banks. Bottles and jars are usually green, clear or brown in colour although there are other colours like blue – this goes in with the green. All these colours can be recycled.

Wow fact: It takes around 30 days for a bottle or jar to return as new to the shelf.

Sometimes the different coloured glass is broken up together and used for aggregate to build roads. However, mixed glass can be separated using a machine with laser beams. The laser beam detects what colour individual pieces of glass are and sends a message back to a computer. The computer fires a puff of air which pushes the pieces of glass into separate coloured glass piles. When the glass has been separated it can be made into new bottles and jars.

Wow fact: Glass is 100% recyclable and can be recycled an infinite number of times without loss of quality, strength and functionality.

Wow fact: The energy saving from recycling just one glass bottle will power a computer for 25 minutes, a TV for 20 minutes, or a washing machine for 10 minutes.

Recycling glass saves huge amounts of energy. This is because recycled glass melts at a lower temperature than the heat needed to make glass from new. By recycling glass you also help conserve habitats from being dug up/mined to obtain more silica, limestone and other natural resources.

Wow fact: The average family uses around 300 bottles and jars every year. If all of these were recycled it would save the equivalent electricity to power a washing machine for 2.5 days, non stop!