Changes Matter Undergo (2)

Which is the Process by Which a Gas Changes to a Solid? Deposition, Evaporation, Freezing, Sublimation

Which is the Process by Which a Gas Changes to a Solid?





The straight answer to this question is Deposition. Deposition is the change of state of matter from gaseous state straight to solid state without passing through the intermediate form which is liquid state. The summary of the processes that matter undergo can be seen in the table below.

FreezingChange of state from liquid to solid
MeltingChage of state from solid to liquid
Boiling/evaporationChange of state from liquid to gas
DepositionChage of state from gas to solid
SublimationChange of state from solid to gas
CondensationChange of state from gas to liquid

I will explain the processes further down in the post, but the scheme below explains the summary of the six changes that matter undergo. It is important to mention that heat is absorbed during melting, boiling and sublimation while heat is given out during freezing, deposition, and condensation.

There are some substances that do not pass through the intermediate state which is liquid state before going over to the other state examples include camphor, naphthalene, ammonium chloride, solid ice solid carbon IV oxide). These substances can easily sublime or be deposited. question is a fundamental basic knowledge of science that deals with the changes that matter undergoes. A deep understanding of the processes leading to the changes in the states of matter  is a fundamental aspect of science that enables one to interpret the changes easily.

However, when it comes to identifying which process involves a gas turning into a solid, a solid turning into a liquid, a liquid turning into a gas, etc, these changes can be slightly confusing since they are somewhat related but subtle understanding makes it very clear. So, let’s dive into this fascinating topic and clear up any uncertainties. Shall we?


I will start with deposition because it is the answer to our question. Deposition is the process by which matter directly transitions from a gas to a solid, without passing through the intermediate liquid state. The deposition process is a very fascinating phase transition because a gas transforms directly into a solid without first passing through the intermediate liquid state, so this means that no liquid is formed during deposition. This process is also known as de-sublimation and is the reverse of sublimation. I know you must be wondering how it is possible to change directly from one phase to another without the intermediate state.

Well, like I mentioned some substances do not form the liquid state and the simple truth is that when the substance gain energy it breaks the force of attraction and go straight to gas or when it loses energy. In nature, deposition is most observed in the formation of frost and snowflakes. For example, in moist formation, when moist air meets a surface that is below the freezing point of water, the water vapor in the air transitions directly from a gaseous state to solid ice, forming frost. This is a common occurrence on cold winter mornings when the temperature drops overnight. The formation of frost on the ground, plants leaves, and other surfaces on earth is a direct result of deposition. Similarly, the formation of snowflakes in clouds is another example. Water vapor in the upper atmosphere sublimates directly into ice crystals, which then aggregate to form snowflakes.

In general deposition typically requires a loss of heat which is drop in temperature or an increase in pressure. When a gas loses enough heat or thermal energy, its molecules slow down and come together to form a solid.

Application of deposition

In the same vein, deposition can also be seen in industries The deposition process is also applied in industries where such application is in the field of thin-film deposition, which is crucial in the manufacture of semiconductors and other electronic components. In this process, a gas containing the desired material is introduced into a vacuum chamber. When the gas meets a cooler substrate, it deposits a thin film of solid material onto the substrate’s surface. This technique is used to create extremely thin layers of metals, insulators, and semiconductors with high precision.

Another industrial application of deposition is in the freeze-drying process used in food preservation and pharmaceuticals. During freeze-drying, a substance is first frozen, and then the surrounding pressure is reduced. Heat is then applied, causing the frozen water in the material to sublime directly into vapor. This vapor is removed, and the material is left in a stable, dehydrated form. To prevent the material from passing through the liquid state and potentially degrading, deposition is utilized to capture and solidify the vapor directly.

Deposition is also a key process in the formation of certain types of mineral deposits. For instance, in volcanic regions, sulfur can be deposited directly from volcanic gases onto the surfaces around fumaroles. These sulfur deposits are valuable for various industrial uses.

Deposition is a critical phase transition with wide-ranging implications. It not only explains everyday natural phenomena like frost formation but also underpins sophisticated industrial techniques that are essential in modern technology and manufacturing.


Melting is the process by which a solid changes from a solid state to liquid state by absorbing little heat energy. The energy absorbed is used to break the force of attraction holding the molecules. Melting is usually associated with heat absorption in order to break the forces of aatraction.

Application of melting

The applications of melting include candle making, geology and metallurgy etc these processes include melting .


Evaporation is the process by which matter goes from liquid to gaseous phase or state. Evaporation is like boiling in the sense that both involve a change of state from liquid to gaseous state. However, boiling takes place at a specific temperature but evaporation can take place at any temperature.  Evaporation usually happens when the water molecules gain enough energy to overcome the attractive forces holding the particles in the liquid phase. The rate of evaporation increases as temperature increases but the evaporation itself takes place at any temperature.

Generally, evaporation takes place when molecules at the surface of a liquid gain enough energy to break free from the bonds holding them together and transition into a vapor. Typically, this process is influenced by factors like temperature and wind speed.

Temperature is a primary factor; higher temperatures provide more energy to water molecules, increasing their kinetic energy and the likelihood of transitioning to vapor. Relative humidity also plays a crucial role. Lower humidity levels mean less water vapor is present in the air, allowing more liquid water to evaporate. Conversely, high humidity slows evaporation since the air is already saturated with water vapor. Wind speed is another important factor; wind moves the saturated air away from the surface of the liquid, replacing it with drier air and thus promoting further evaporation. Surface area also affects evaporation; a larger surface area allows more molecules to escape simultaneously.

Evaporations vs Boiling

The key differences between boiling and evaporation is that boiling takes at the bulk surface while evaporation takes place at the surface of the molecules.

The second difference between evaporation and boiling is that evaporation can take place ant any temperature but boiling takes place at a particular temperature.

In nature, evaporation is very important because it ensures a return of moisture in the water cycle. Evaporation from oceans, lakes, and rivers supplies moisture to the atmosphere, driving weather patterns and influencing climate. It is also essential in agriculture, evaporation impacts irrigation efficiency and soil moisture levels, affecting crop growth and yield.

Application of evaporation

In industrial applications, evaporation is used in industrial processes like drying, concentration of solutions, and cooling. For example, cooling towers in power plants rely on evaporation to dissipate heat. Additionally, desalination plants use evaporation to separate salt from seawater, producing fresh water.

Changes In States Of Matter Science Poster In Beige Modern Style
Changes In States Of Matter Science Poster


Freezing is the process where a liquid turns straight into a solid. For example, when you put water in a freezer, it changes straight into a solid i.e. ice. It is important to note that during freezing, the substance loses heat energy which enables the molecules to come together.

I live in Germany, and I remember coming back from work and I saw frozen water like a small lake or river. This happens during the winter seasons. Freezing occurs when the temperature of a liquid drops below its freezing point, this causes the molecules to lose energy and come together in a more structured arrangement, forming a solid.

Application of freezing.

Freezing is applied in several industries including food preservation, pharmaceuticals, etc I work in a food production industry where they make cheese, biscuits, etc but I remember that in the place where they make cheese, there are cold places like freezers, but this is to help preserve the food.


Sublimation is the process in which a solid changes directly into a gas, without changing into a liquid state. Sublimation usually requires heat to overcome the force of attraction holding the molecules and this helps the substance to change directly to the gaseous phase. For example, an iodine molecule can change from a solid state to a gaseous phase by absorbing little heat and breaking the forces of attraction..

Sublimation simply occurs when a substance absorbs enough energy that its molecules break free from the solid structure and enter the gas phase. However, sublimation is usually thermodynamically suitable for low pressure.

Application of sublimation

Sublimation can be applied in freeze drying, purification of substances etc

Deposition vs sublimation

It is important to note that deposition is the change of a gaseous state to a solid state without undergoing or passing through the liquid state while sublimation on the other hand is the change of state from a solid state to the gaseous state without passing through the liquid state.


The conclusion of these is basically from the understanding of the processes which we have defined in the post above and proper understanding of the interconversion of matter from solid to liquid or gas and vice versa.

Which is the Process by Which a Gas Changes to a Solid? Deposition, Evaporation, Freezing, Sublimation?

To summarize and reemphasize the answer to this question, it is important to mention again that the answer to this question is deposition.

So, what is the process by which a gas changes to a solid? The answer is deposition. Deposition is a unique transformative process and is quite different from others like evaporation, freezing, and sublimation, which involve different state changes. These processes occur distinctly in nature whether through the formation of frost, drying clothes, freezing water, or observing dry ice.

It is very important that understanding these processes not just deepen our appreciation of the natural world, but also emphasizes the wondrous complexity of simple physical transformations. So matter changes occur in nature in several transformative ways.

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