Most of the glass that we use is made in a factory. It is made from a mix of sand and other materials. When the mixture is heated, it turns into a thick liquid that looks like see-through treacle. The hot liquid cools down and turns into hard glass.

 

 

 

 

 

Glass is made from natural materials.

Glass is made from natural materials – sand, soda and lime. These materials are cheap and plentiful, and found all over the world. They are dug out, or quarried, from the ground. Other materials are sometimes used to make certain types of glass. However, sand is usually the main ingredient.

 

 

 

 

 

Other materials are added to make special types of glass.

Adding other ingredients to the basic glass mixture makes different types of glass. Coloured glass is made when different chemicals are added to the glass mixture. Thin wires are sandwiched inside a cooling glass mixture to make wire glass which is very strong.

 

 

 

 

 

Some natural glass is found in the Earth.

Natural glass forms in the mouth of a volcano. The heat of the volcano melts sand and other materials to form natural glass, called obsidian. This glass was first used by humans to make very sharp tips for spears!