There are three states of matter: solids, liquids and gases. In many cases, the same element can exist in all three states.
When matter changes from one state to another it is called a phase transition. Examples include:
- Gas to solid phase transitions are known as "deposition."
- Gas to liquid phase transitions are known as "condensation."
- Liquid to gas phase transitions are known as "vaporization."
- Liquid to solid phase transitions are known as "freezing."
- Solid to liquid phase transitions are known as "melting."
- Solid to gas phase transitions are known as "sublimation." In most cases, solids turn into gases only after an intermediate liquid state.
There are many examples of matter going through each of these transitions.
Under certain circumstances, gas can transform directly into a solid. This process is called deposition.
- Water vapor to ice - Water vapor transforms directly into ice without becoming a liquid, a process that often occurs on windows during the winter months.
- Physical vapor to film - Thin layers of material known as "film" are deposited onto a surface using a vaporized form of the film.
- Water vapor to dew - Water vapor turns from a gas into a liquid, such as dew on the morning grass.
- Water vapor to liquid water - Water vapor fogs up glasses when moving into a warm room after being in the cold
- Water vapor to liquid water - Water vapor forms water droplets on the glass of a cold beverage.
- Water to steam - Water is vaporized when it is boiled on the stove to cook some pasta, and much of it forms into a thick steam.
- Water evaporates - Water evaporates from a puddle or a pool during a hot summer's day.
- Water to ice - Water becomes cold enough that it turns into ice. In fact, every known liquid (except for helium) is known to freeze in low enough temperatures.
- Liquid to crystals - Most liquids freeze by a process that is known as "crystallization," whereby the liquid forms into what is known in the scientific world as a "crystalline solid."
- Solid to liquid - Melting occurs when something that is solid turns back into a liquid; it is the opposite of freezing.
- Ice to water - Ice melts back into water when it is left out at temperatures above the freezing point of 32 degrees.
- Rocks to lava - Rocks in volcanoes can be heated until they are molten lava.
- Metal to molten liquid - Metals such as steel and bronze can be molten down. They can also be reformed as solids.
- Dry Ice - Solid carbon dioxide is known as "dry ice" and sublimates at room temperature.
- Freeze-drying - Water can be sublimated in a food product by using a vacuum.
Now you have some examples of gas to solid and can better understand how transitions occur between different states of matter.