What is static electricity?
Static electricity is the branch of physics that is over the study and analysis of the behavior of electrical charges in an equilibrium state, or put another way, the effects generated in bodies as a result of their electrical charges, whether attraction or repulsion. This effect is known as the electrostatic phenomenon.
Static electricity is understood to be the phenomenon that occurs between two bodies that accumulate electrical charges, either by processes of induction or friction. This accumulation of energy can occur, for example, if two materials rub against each other, passing electrons from one surface to another through the energy level differential.
If an electrically charged material attracts or repels the electrons of another material, what is known as an induced charge occurs: an area with a higher positive charge is generated in the second material, causing attraction.
With static electricity, the load level depends on factors such as the material (whether it is a conductor, semiconductor, or insulator), as well as its physical and electrical properties, humidity, temperature, pressure, and the bodies’ speed of separation.
When was static electricity discovered?
The first signs of the study of static electricity date back to the time of the ancient Greeks, when the philosopher Thales of Miletus (624 BC – 546 BC) identified strange behaviors based on friction between amber and fabrics such as wool, generating an attractive force on objects with static electricity.
Later, in the 17th century, the first analyses of the relationship between electricity and magnetism were carried out with the aim of improving the accuracy of magnetic compasses. Italian scientist Niccolo Cabeo analyzed studies by British physicist William Gilbert, and he concluded that there were forces of attraction and repulsion between bodies in accordance with their characteristics.
In 1733, the French physicist and chemist Francois de Cisternay du Fay proposed the existence of two types of electrical charges: negative and positive. Then, in 1785, the French physicist Charles Coulomb also formalized the quantitative concepts of electrical forces in a treatise. He formulated Coulomb’s Law, which advanced propositions on attraction and repulsion with static electric charges. This law was supplemented by Gauss’s theorem, which defined almost all electrostatic phenomena.
How is static electricity generated?
Static electricity occurs when two or more bodies come into contact and separate again. This is a phenomenon between surfaces that results in the transfer of electrons from one atom to another. It can be generated as follows:
- Electric charge by rubbing: some bodies can be charged after being rubbed against each other, producing a transfer of electrons. This way, one object is electronegatively charged, and the other is electropositive.
- Electric charge by induction: this does not require contact between objects to generate an electrical charge. Conversely, if a material has a negative charge and comes near an electrically neutral body, the electrons of the latter will be repelled by the excess electrons of the former. It will therefore move inside the containing material to get away from the charged body.
How does static electricity manifest in everyday life?
- Rubbing a piece of glass with a cloth: when the cloth is thick enough, the glass, which is an insulating material, is electrically charged and will attract any small particles that are near.
- Combing: the plastic material the comb is made from is insulating; when running it through the hair repeatedly, it will be charged with electrons, making the hair rise.
- Printing on photocopying or laser machines: the light beam that illuminates the image or text in the scanning process transfers electrical charge to a photosensitive drum. The toner, which has magnetic properties, adheres to the parts sensitized by the light beam when passing through the drum. Then, when the paper passes through the drum, the toner material peels off and adheres to the surface, transferring the drum’s contents.
- Dragging your feet in socks across a carpet: static electricity accumulates in the body, and if someone is touched afterwards, an electric shock can be felt.