What is the difference between freezing and solidification.
What is the difference between freezing and solidification.
Freezing is one kind of solidification, but some kinds of solidification are not freezing. Both processes imply a transition from a liquid or gas (usually a liquid) to a solid state. However, this process can happen in several ways.
The most common transition of this kind is freezing. Most pure substances can exist in solid, liquid, or gaseous states, depending on their temperature and the ambient pressure. At higher temperatures, the atoms or molecules have more energy and can be thought of as being vibrating most energetically in a gas, less so in a liquid, and least in a solid.
In freezing (which is the opposite of melting) therefore, a substance simply loses energy as it cools down and forms a crystalline (or sometimes amorphous) solid. Adding more energy by reheating the material will return it to a liquid - and eventually gaseous - state. Therefore, freezing is reversible.
Some materials can go directly from gas to solid with no liquid state between, and vice versa. This is called sublimation, but the principle is otherwise the same.
As an example of a kind of solidification that is not freezing, epoxy adhesives will solidify when the resin and hardener are mixed. This results from a chemical reaction in which the two liquids react to form a new substance, which is solid. This process is not reversible by reheating.
Likewise, plaster and concrete solidify by mechanisms other than freezing.
Freezing is one kind of solidification, but some kinds of solidification are not freezing. Both processes imply a transition from a liquid or gas (usually a liquid) to a solid state. However, this process can happen in several ways.
The most common transition of this kind is freezing. Most pure substances can exist in solid, liquid, or gaseous states, depending on their temperature and the ambient pressure. At higher temperatures, the atoms or molecules have more energy and can be thought of as being vibrating most energetically in a gas, less so in a liquid, and least in a solid.
In freezing (which is the opposite of melting) therefore, a substance simply loses energy as it cools down and forms a crystalline (or sometimes amorphous) solid. Adding more energy by reheating the material will return it to a liquid - and eventually gaseous - state. Therefore, freezing is reversible.
Some materials can go directly from gas to solid with no liquid state between, and vice versa. This is called sublimation, but the principle is otherwise the same.
As an example of a kind of solidification that is not freezing, epoxy adhesives will solidify when the resin and hardener are mixed. This results from a chemical reaction in which the two liquids react to form a new substance, which is solid. This process is not reversible by reheating.
Likewise, plaster and concrete solidify by mechanisms other than freezing.
