At first glance, the question “why is water wet” seems rather strange, because it is water that makes everything around wet. However, it is not without meaning; moreover, scientists for a long time could not answer it, and even continue to argue whether water is wet at all. The very concept of “wet” usually implies our sensation when in contact with water. But the skin does not have receptors that are responsible for the sensation of moisture. That is, we physically cannot feel whether the water is wet or not, but somehow it still happens. It was only relatively recently that French scientists managed to clarify the situation.
Scientists for a long time could not understand why water seems wet to us. Photo source: medicinaplus67.ru
Why water seems wet to us
To find the answer to this question, employees of Loughborough University, together with Oxylane Research, conducted an experiment in which 13 male volunteers were involved. All men were exposed to water at different temperatures – 25 degrees, 30 degrees and 35 degrees.
The researchers exposed water to different parts of the body – the hairy skin of the forearm, the hairless skin and fingertips. In some cases, participants had their nerves blocked before pouring water over their skin.
Cold water feels stronger on the skin than warm water. Photo source: sputnik.by
All participants were asked to report how strongly they felt the water. As you might guess, in all cases the results were different. Volunteers experienced the strongest feeling of moisture when they were exposed to cold water. And what's most interesting is that skin covered with hair is more sensitive to moisture than skin without hair.
Volunteers felt warm water to a lesser extent. And when the nerves were blocked, the sensation of water disappeared altogether. As reported by Mail Online, based on the results obtained, scientists came to the conclusion that the feeling of “wet” water is actually a combination of two sensations – temperature and texture.
The temperature of the water is usually different from the temperature of the skin – it is cooler. When the brain receives information about temperature and texture, it immediately understands that the skin is in contact with water. Moreover, this happens only because a person already has knowledge about what sensations water causes.
As the researchers themselves say, our idea of humidity is an “illusion of perception” based on already available information. That is, how we feel when we are wet corresponds to what we think we should feel based on the temperature difference of the water and its texture. Animals, for example, cats, who do not like it, sense water in the same way.
Scientists have called our sensation of water an “illusion of perception.” Photo source: dzen.ru
However, if the water temperature does not differ from the skin temperature, we may not feel it. For example, if a drop of warm water hits the skin, a person may not notice it at all.
Is water really wet?
Another concept we use in everyday life is “moist” or “wet”, as an indicator of the water content in physical bodies and environments. For example, when we say that things are wet after washing, we mean that there is water in them. From this point of view, we can say that all liquids, including water, are truly wet.
However, scientists debate whether water is wet or moist. The fact is that, from a scientific point of view, humidity is defined as the ability of a liquid to maintain contact with a solid surface. This means that water itself is not wet. However, due to its ability to maintain contact, for example with the skin, it gives us the wet sensations described above. Thus, if we take a philosophical approach, we can say that water is both wet and at the same time not wet.
Water is wet in our understanding due to several molecular properties. Photo source: www.slavicsac.com
Why is water wet
If we talk about the concept that we use in everyday life, water is wet due to several of its molecular properties at the same time. For example, it is able to stick to surfaces due to adhesion, that is, due to the force of attraction between molecules of different substances. In other words, water interacts with the molecules of the surface material.
Moreover, water molecules are polar, that is, they have positively and negatively charged areas. This allows them to interact with other polar molecules or ions on surfaces. Thus, adhesion between surfaces and water is enhanced.
Also, water, like all liquids, can spread. This property is due to both adhesion and cohesion, that is, the attraction between water molecules. In addition, it can penetrate and fill the pores and microcracks of materials, especially hydrophilic (water-loving). At the same time, water changes the texture and temperature of surfaces, as a result of which they become wet in our understanding.
Water forms droplets due to surface tension. Photo source: naked-science.ru
Water also has surface tension, which causes its surface to behave like an elastic film. The reason lies in the forces of attraction between the molecules of the liquid. It is thanks to this that water forms drops, and some insects can even walk on it. By the way, the combination of adhesion and surface tension allows water to rise through thin tubes or pores.
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Finally, we note that on Earth we are faced with only three states of water – liquid, solid (ice) and gaseous. However, in reality there are more such conditions. For example, we previously reported that scientists have discovered a second liquid state of water. You can read more about this at the link.