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Is making glass from sand a physical or chemical change?
Transcript of Is making glass from sand a physical or chemical change?
by Oliver Secules
Physical versus Chemical Change
What happens when lightning strikes sand?
When lightning strikes sand it creates a kind of glass called fulgurite. Fulgurite is a hollow glass that is made underground and can stay intact for centuries until erosion brings it to the surface. Fulgurite can often be mistaken for a stick, and is extremely fragile.
Actually, it's both, because there is many, many different types of glass.
Here is a fun video about glass!
How is glass made?
To make glass, first you take silica sand, then recycled glass, then soda ash, then limestone, and finally heat it in a furnace at 1800 degrees Celsius and if you want to make it flat then pour molten glass over molten tin.
Glass is not a solid and it is also not a liquid, it is a substance called an amorphous solid, which is halfway between a liquid and a solid.
Making soda lime glass, which is what's usually used in everyday objects, is a chemical change, because you have a totally new substance which you cannot separate.
On the other hand, when lightning strikes sand and makes fulgurite, it is still sand, because it just changed state and no new compounds were formed.
Liquid or solid?
An example of a physical change is chopping up potatoes.
An example of a chemical change is an iron nail rusting.
A physical change is a reversible change, such as melting wax, which you can solidify after melting.
A chemical change is an irreversible change such as spoiling food which you cannot unspoil.
A sample of fulgurite.
Physical or chemical change?