We encounter static electricity everywhere in our daily lives. For example, when you take off a wool sweater, you can feel your hair being pulled along with it and making a characteristic crackling sound. Also, many probably remember the school experiment with an ebonite stick, which clearly demonstrates how static electricity occurs. But despite the fact that this phenomenon is extremely common, for more than 2,500 years scientists could not find a clear explanation for how static electricity occurs. But now, it seems, this mystery has been solved.
We regularly encounter static electricity in everyday life, but only now have scientists found an explanation for it. Photo source: jacksonandsons.com
What is static electricity
Static electricity is a set of phenomena associated with the generation and maintenance of an electric charge on the surface of dielectrics. Simply put, rubbing objects against each other generates static electricity. It can even occur when we simply pet a cat or shuffle our feet on a carpet.
People first learned about this phenomenon in ancient times. Presumably, the first mention of it belongs to the ancient Greek philosopher Thales of Miletus. More than 2,500 years ago, he discovered that amber rubbed against wool begins to attract light objects, such as feathers or pieces of dry grass.
Static electricity occurs as a result of friction between two objects. Photo source: news365.ru
Perhaps you conducted similar experiments at school – rubbed a plastic ruler or, for example, a pen against a wool sweater or hair, and it began to attract paper. The reason for this phenomenon is that when different objects are rubbed against each other, a redistribution of electrons occurs with the formation of electrical layers with different signs of electrical charges on the surfaces of these objects.
In fact, atoms and molecules of one substance that have a stronger attraction tear electrons from another substance. In fact, this is where scientists' knowledge of static electricity stalled for a long time. Why friction generates static electricity in any insulators was unclear.
Why does static charge arise
Researchers at Northwestern University (USA) have modeled static charge at the nanoscale. This allowed them to discover that rubbing materials together causes changes in their surfaces. That is, friction bends tiny protrusions on the surface of these materials. These bent, deformed protrusions cause stress. The authors report this in Physical Review Letters.
Diagram of the origin of static electricity. Photo source: naked-science.ru
The formation of static electricity, according to scientists, is related to the concept of “elastic shear.” This phenomenon occurs whenever a surface resists sliding. The front and back of a sliding object experience different forces associated with resistance. This difference in force causes a shift in electrical charges. As a result, different electrical charges accumulate on the front and back of the object.
For example, when you push a cup on a table, it starts to move, but resists the movement, and different deformations occur at the front and back. This causes electric charges to move and generate current.
It must be said that researchers discovered back in 2019 that roughness of surfaces rubbing against each other plays a key role in the formation of static electricity. However, it was only now that we were able to fully understand how this works.
Static electricity can damage computer chips. Photo source: izmerenia.by
Can static electricity be dangerous
Usually, static electricity, which makes your hair stand on end, only makes you smile. Various experiments with it are perceived simply as fun. However, according to scientists, in fact, it is not as harmless as many assume. For example, at explosive industrial facilities, sparks of static electricity can cause a fire or even an explosion.
Also, static electricity can interfere with the uniform dosing of powdered pharmaceuticals. It poses an even greater threat to computer chips, as well as components of electrical circuits.
At the same time, static electricity can be used for good. For example, it can be accumulated and used to recharge gadgets. Also, earlier, scientists found out that charging coffee beans with static electricity affects how they are ground and even changes the taste of the drink.
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According to the researchers, understanding how and why static electricity occurs will help solve many problems associated with it in the future, and will also allow them to find useful applications for it.