Changes of State of Matter

What are the changes of state of matter?

Changes in the state of matter refer to the transformations that matter undergoes from one state to another without changing its composition. These changes occur when pressure and / or temperature vary.

On Earth, solid, liquid, gaseous and plasmatic states naturally manifest themselves. The changes of state that occur between these are: vaporization, fusion, solidification, sublimation, reverse sublimation, ionization and deionization.

Let’s see what they are, how they are produced and what are the most common examples in daily life.


Solidification is the change from a liquid to a solid state. It occurs when the temperature of a liquid or fluid drops significantly.

How does solidification occur? When the temperature of the fluid drops, the particles get closer and closer to each other, until they become so compact that the movement between them is reduced. This approximation and lack of mobility between the particles is what gives the solids firmness.

The maximum point at which the fluid hardens is known as the freezing point .


  1. Ice formation.
  2. Chocolate hardening.
  3. Hardening of molten metals (jewelery, work tools, etc.).
  4. Manufacture of bar soaps.
  5. Gelatin hardening.

Melting or melting

Melting or melting is the change from a solid to a liquid state. Fusion occurs when the solid is exposed to an increase in temperature.

How does melting or melting occur? When the temperature rises considerably, the solid matter particles begin to separate from each other. As the separation is greater, the particles gain more movement. Consequently, matter begins to gain a fluid appearance and loses its shape. That is, the solid turns into a liquid.


  1. Thawing of the polar caps.
  2. Melted chocolate.
  3. Melted butter for cooking.
  4. Melted candle wax (paraffin).
  5. Melting of popsicle ice creams exposed to the heat of the environment.

Vaporization or evaporation

Vaporization is the change from a liquid to a gaseous state. Vaporization occurs when a liquid is exposed to a rise in temperature.

How does vaporization occur? Vaporization is a process that proceeds steadily and slowly in certain fluids, but accelerates when the liquid reaches the boiling point .

Under these conditions, the particles begin to move away from each other. The interaction between them is broken and, therefore, their movement becomes expansive, giving rise to the formation of the gaseous state.


  • Steam of boiling water.
  • Drying a wet floor.
  • Sweat evaporation.
  • Drying clothes in the open air.
  • Cloud formation due to evaporation of terrestrial water.


Condensation is the change from gaseous to liquid state. Condensation occurs when the temperature drops and / or the pressure in the environment rises.

How does condensation occur? When the temperature drops and / or the pressure rises, the particles that make up the gas begin to get closer to each other, so that they lose part of their mobility. In this way the change from the gaseous state to the liquid takes place.


  • The rain.
  • The perspiration of a glass of cold liquid.
  • Dew.
  • Fogging of glass and mirrors.


Sublimation is the direct change from the solid to the gaseous state. In this case, there is no passage through the liquid state. In fact, the word sublimation comes from the Latin sublimare , which means ‘to rise up’.

Sublimation occurs when a solid kept at an extremely low temperature comes into contact with a higher temperature, within a certain pressure.

How is sublimation produced? For all substances there is a point of temperature and pressure in which the solid state, the liquid and the gas coexist in equilibrium, which is called the triple point .

When the temperature of the solid state is below the triple point and, in addition, the vapor pressure is low enough, there are no conditions for the formation of liquid. Then, any contribution of energy (heat), no matter how small, causes the particles of the solid to abruptly separate and expand in space in the form of gas.

For example, dry ice is a solid block of carbon dioxide (CO 2 ) and is stored at a temperature of -78 ° C, that is, below the triple point. When dry ice is exposed to room temperature, at a pressure below 5.2 atmospheres, it transforms into a gas directly. This is sublimation.


  • Dry ice sublimation.
  • Naphthalene sublimation.
  • Dye sublimation.
  • Chemical sublimation for medicines.

Reverse sublimation or deposition

Reverse sublimation consists of the direct change from the gaseous to the solid state. Reverse sublimation is also known as deposition, reverse sublimation, regressive sublimation, desublimation, or crystallization.

Reverse deposition or sublimation occurs when gas comes into contact with very low temperatures quickly or suddenly.

How is reverse sublimation or deposition produced? When a gas or vapor is exposed to very low temperatures and in certain humidity conditions, it loses its heat energy rapidly. Thus, its particles are compacted, and it passes to the solid state.


  • Snow.
  • Frost formation
  • Contrails of aircraft in the sky.
  • Soot formation in chimneys.


Ionization is the change from gas to plasma. This process takes place when a gas is heated.

How does ionization occur? When a gas is heated, the particles that make up the gas begin to move faster and collide with each other. This increases the energy level, causing the outermost electrons of the atoms to be lost and the atom to be transformed into an ion.

Part of the energy of these atoms and electrons can give rise to photons. This process causes the gas to glow, which gives rise to plasma.


  • Lightning from thunderstorms.
  • The polar auroras (aurora borealis and aurora australis).
  • Neon lights.
  • Plasma TVs.
  • Plasma lamps.


Ionization is the change from gas to plasma. This is the reverse process of ionization. It occurs when an electrically charged gas cools.

How does ionization occur? In contrast to ionization, deionization is a process in which a gas cools, causing it to lose its energy charge.


  • The smoke that is generated during the metal welding process.
  • The smoke from a freshly extinguished flame.