States of Water (Meaning and Explanation)

We explain what the states of water are, the characteristics of each one and how the change between one and another occurs.

What are the states of water?

We all know what water is and we know its three presentations, known as the physical states of water: liquid (water), solid (ice) and gaseous (vapor). These are the three ways in which water can be found in nature, without changing its chemical composition at all: h₂O (hydrogen and oxygen).

The state of the water It depends on the pressure around it and the temperature at which it is found that is, the environmental conditions. Therefore, by manipulating these conditions it is possible to convert liquid water into solid or gaseous, or vice versa.

Given the importance of water for life and its abundant presence on the planet, Their physical states are used as a reference for many measurement systems and thus allow comparisons to be made with other materials and substances.

Properties of water

states of water properties surface tension — Insects and spiders can move on the surface of the water due to its surface tension.

The water It is an odorless, colorless, tasteless substance with a neutral pH (7, neither acidic nor basic). It is composed of two hydrogen atoms and one oxygen atom in each molecule.

Its particles have an enormous cohesive force that keeps them together, so that has a significant surface tension (some insects take advantage of it to “walk” on water) and a lot of energy is required to alter their physical states.

Water is known as the “universal solvent”, because Many more substances can dissolve in it than in any other liquid. Furthermore, it is a fundamental compound for life, abundantly present in all organisms. The water covers two thirds of the total surface of our planet.

liquid state

states of water liquid waterfall — In its liquid state, water is fluid and flexible.

The state that we most associate with water is liquid, its state of greatest density and incomprehensibility and also the most abundant on our planet.

In its liquid state, the particles of water are close together, although not too close. Therefore, liquid water presents flexibility and fluidity typical of liquids and loses, however, its own shape to adopt that of the container that contains it.

Therefore, liquid water requires certain conditions of energy (heat, temperature) and pressure. At a temperature between 0 and 100º C, and normal atmospheric pressure conditions, Water is in a liquid state. However, it is possible to exceed its boiling point if it is subjected to higher pressures (superheated water) and can reach, in a liquid state, the critical temperature of 374° C, the maximum temperature at which gases can liquefy.

liquid water It is commonly found in seas, lakes, rivers and underground deposits but also contained in the bodies of living beings.

Solid state

states of water solid ice — The ice that covers lakes is less dense than water.

The solid state of water commonly known as ice and is reached when descending its temperature at 0 °C or less. A curiosity about frozen water is that it gains volume compared to its liquid state. That is to say, ice has a lower density than water (which is why ice floats).

Ice is hard, fragile and transparent in appearance, ranging from white to blue, depending on its purity and the thickness of its layers. Under certain conditions, it can temporarily remain in a semi-solid state, known as snow.

solid water It can commonly be found in glaciers, on mountain tops, in frozen soils (permafrost) and on the outer planets of the Solar System, as well as inside our food freezer.

gaseous state

states of water gaseous vapor — When we exhale on a cold day we can see water in a gaseous state.

The gaseous state of water It is known as steam or water vapor and is a usual component of our atmosphere, present even in each exhalation we take. In conditions of low pressure or high temperature, water evaporates and tends to rise, since vapor is less dense than air.

The change to the gaseous state occurs at 100° C as long as one is at sea level (1 atmosphere). The carbonated water It makes up the clouds we see in the sky, it is found in the air we breathe (especially in our exhalations) and in the fog that appears on cold and humid days. We can also see it if we put a pot of water to boil.

Changes in water status

As we have seen in some of the previous cases, water can change from one state to another, simply by varying its temperature conditions. This can be done in one direction or another and we will give each different process its appropriate name:

Evaporation Transformation from liquid to gas, increasing the temperature of the water to 100° C. This is what happens with boiling water, hence its characteristic bubbling.
Condensation Reverse process: transformation from gaseous to liquid, due to heat loss. This is what happens to water vapor when it condenses on the bathroom mirror: the surface of the mirror is colder and the vapor that settles on it becomes liquid.
Freezing Transformation from liquid to solid, lowering the temperature of the water below 0° C. The water solidifies, producing ice, just as it happens in our freezers or on mountain peaks.
Melting Reverse process: transformation of solid water into liquid, adding heat to ice. This process is very everyday and we can see it when we add ice to our drinks.
Sublimation Process of transformation from gas to solid, in this case from water vapor, to ice or snow directly. For it to occur, very specific temperature and pressure conditions are required, which is why this phenomenon occurs at the top of mountains, for example, or in the droughts of Antarctica, where water in a liquid state cannot exist.
Reverse sublimation Reverse process: transformation of a solid directly into a gas, that is, from ice to steam. We can witness it in very dry environments, such as the polar tundra itself or on mountain summits, where as solar radiation increases, much of the ice sublimes directly into gas, without going through a liquid stage.

Hydrological cycle

The hydrological cycle or water cycle is the circuit of transformations that water experiences on our planet, passing through its three states gaining and losing temperature and moving from place to place.

It is a complex circuit that involves the atmosphere, oceans, rivers and lakes and ice deposits in the mountains or at the poles. Thanks to it, the planet's temperature remains stable dry regions are hydrated and rainy regions dry, preserving a climatic balance that allows life throughout its different seasons.

Continue in: Water cycle