Glass
Glass is a very odd substance, is it a solid or a liquid? There are many reasons why it can be considered either of the two, but still most people are unsure of its state. Glass may be a state of matter that is neither solid nor liquid.
A liquid has viscosity, which is a measure of its resistance to flow. So water may move very quickly because it has a high viscosity, but oil has a high viscosity so it moves slower. If something were to have a very high viscosity then it may seem like a solid but it would be an amorphous solid. An amorphous solid is a liquid that looks like a solid but doesn't have crystals so it just sits there for a long time and slowly moves.
A solid has viscoplasticity, which is the resistance to flow under plastic deformation. If you were to punch plastic with your hand it would deform then go back to shape, but if you were to hit it with a steel pipe there would be a dent in the plastic and it wouldn't go back to its original form. So the viscoplasticity is like how much of a force you have to put on it until there is a deformation. Some materials don't flow but creep these materials are known as plasticity materials. The only way they can be deformed is to be held under stress (pressure) for a constant amount of time.
Glass is a very odd substance, is it a solid or a liquid? There are many reasons why it can be considered either of the two, but still most people are unsure of its state. Glass may be a state of matter that is neither solid nor liquid.
A liquid has viscosity, which is a measure of its resistance to flow. So water may move very quickly because it has a high viscosity, but oil has a high viscosity so it moves slower. If something were to have a very high viscosity then it may seem like a solid but it would be an amorphous solid. An amorphous solid is a liquid that looks like a solid but doesn't have crystals so it just sits there for a long time and slowly moves.
A solid has viscoplasticity, which is the resistance to flow under plastic deformation. If you were to punch plastic with your hand it would deform then go back to shape, but if you were to hit it with a steel pipe there would be a dent in the plastic and it wouldn't go back to its original form. So the viscoplasticity is like how much of a force you have to put on it until there is a deformation. Some materials don't flow but creep these materials are known as plasticity materials. The only way they can be deformed is to be held under stress (pressure) for a constant amount of time.