What are the classification methods and categories of static electricity?

Classification Methods and Categories of Static Electricity

One, classified by the method of electrification

① Contact friction separation electrostatics

Two different objects come into contact, rub against each other, and then separate, each producing an equal amount of charges with opposite polarities. This method of charging is widely found in various industries and daily life.

② Electrostatic Induction Charging

When a neutral object approaches a charged body, or a charged body moves closer to a neutral object, due to the electric field of the charged object, the neutral object develops an opposite charge at the end closest to the charged body, and a charge with the same polarity at the distant end. This method of electrification is also widely present.

Electromagnetic Induction Charging

Power for modern industry and daily life, such as for motive and lighting electricity, is generated using the principle of electromagnetic induction. The application of static electricity technology also involves the use of electromagnetic induction to transform low-voltage electricity into high-voltage electricity, a new application of this technology.

④ Ray-electrification air ionization

Air and insulators become ionized and charged when exposed to α, β, and γ radiation from radioactive isotopes.

⑤ Electrostatic Charge from Changes in the Three States of Matter

Water is a good conductor, and below 4°C, it transitions from liquid to solid, forming ice. When ice forms, it carries an electrical charge. As liquid water turns into water vapor—a gaseous state—it also becomes charged. When water vapor rises and cools, it condenses into droplets, snow, or hail, which are also electrically charged.

⑥ Molecular Fission Electrolysis

Deformation, cracking, and breaking of objects can cause neutral molecules to split and become charged, and sometimes even discharge sparks can appear at the moment of sudden cracking or breaking.

Polarization Charging

In an electric field, the positive and negative charges of some non-conductive dielectrics, under the influence of the electric field force, will slightly shift in opposite directions. For most polar molecules, their dipoles must align in a specific direction, resulting in one end having a negative charge and the other end a positive charge, commonly referred to as dielectric polarization.

Some dielectrics exhibit piezoelectricity when subjected to pressure, and when subjected to an electric field, they experience a dipole moment tilt. The former is known as the piezoelectric effect, and the latter as the piezoelectric thermal effect, collectively referred to as piezoelectric polarization.

Electret materials retain polarization even in the absence of an external electric field, forming an electric field around them. Such objects are called electrets. Depending on the method of preparation, electrets can be categorized into thermal electrets, electrostatic electrets, photoelectrets, radioactive electrets, and electromagnetic electrets, among others.

⑧ Field Emission Electrostatic

In any electric field, a particle becomes an electric dipole. If the electric field is very strong, electrons in the particle may be ejected from the negative end due to the high electric field, a process known as electron field emission. Alternatively, positive ions in the particle may be ejected from the positive end, referred to as positive ion field emission. This method allows for the rapid acquisition of a large number of electrons, which can be used in short-pulse X-ray systems via electron field emission and for exposure in high-speed photography.

II. Categorization by Conductive Bodies

Solidly charged

Electrification phenomena during production processes such as demolding, baking, winding, conveying, and cutting for plastics, rubbers, films, papers, films, textiles, and other materials.

② Liquid Electrification

Electrification phenomena during loading, unloading, and transportation processes of various insulating oils, insulating reagents, and oil sludge water.

③ Gas Ionized

Emission of pressurized gases, vented gases, steam vapor, steam clouds, and charged gases in pipeline flow.

④ Electrostatically charged powder

Electrically charged operations for plastic powder, grain powder, chocolate, milk powder, etc., including crushing, sifting, and air conveying.

⑤ Human Body Electrified

Human physiological changes or physical activities may exhibit electrical properties in various organs and tissues, such as the resting potential of human cell membranes, which is approximately 100 MV.

⑥ Bioelectric

Many creatures in nature are electrically charged. For instance, bees, whose feet are coated with fine hairs that collect pollen, can firmly attach it to their bodies due to the 6-7V static electricity on their feet, which attracts the pollen. In the sea, there are electric eels that can generate hundreds of volts of potential, with their power-generating organs being just a few micrometers in size. It is said that there is also an electric tree in Africa.

III. Classification by Charge Properties

Polarization can be categorized into unipolar charge, bipolar charge, positive charge, and negative charge for pressure polarization.