Static electricity is nothing but accumulation of static charges. This article gives a detailed insight on how static electricity is created.
The separation of charges in static electricity can be generated by several ways like contact-induced charge separation (triboelectric effect), heat-induced charge separation (pyroelectric effect), pressure-induced charge separation (piezoelectric effect) or charge-induced charge separation (electromagnetic induction).
Static electricity finds a variety of applications in pollution control, air fresheners, etc. Let’s discuss in detail.
Is static electricity useful?
Apart from the spark that we notice in static electricity and the discussion on how static electricity is created, it has wide range of benefits in our everyday life.
Static electricity is used in:
Printers and photocopiers
Photocopiers are the machines that work using the principle of static electricity to make copies of documents or other visual images very quickly and with ease. The device is designed in such a way that positive charges are generated on a photoreceptor drum and the copy paper. The copy paper is where the images would be printed. A powder which transfers the image from the source to the copy paper, known as toner, will be negatively charged.
As opposite charges attract each other, the toner transfers image on the copy paper and the required copied document or image can be generated. Thus printers and photocopiers work using static electricity.
Air fresheners at work locations deploy static electricity to purify the surrounding air. Air ionizers are often purchased at homes. The dust particles, smoke or any other harmful particulate matter in the air will get charged as the device strips away electrons from these particles. The device contains a plate that is oppositely charged to that of the particles’ charge. Since opposite charges attract, the unwanted particles get attracted to the plate and hence purifies the air.
Van de Graaff generator
A van de Graaff generator works using static electricity and generates high voltages.
It consists of a motor, two rollers, an insulated belt, brushes, and a metal sphere. Motor turns the belt around the rollers. The lower roller is made of a material that has triboelectric properties. As the belt turns around the lower roller, the electrons from the insulated belt get captured by the roller. Gradually, more are more charges get accumulated on the roller. Now these charges repel the electrons from the tip of brushes. At the same time, it attracts electrons from the air molecules present in between the roller and the brush assembly.
Hence, positively charged air molecules get carried away from the negatively charged roller by the belt, thereby belt getting positively charged and moves towards the upper rollers. The upper roller repels the positive charge on the belt. The upper roller touches the upper brush and the brush, in turn, is connected to the inside of a metal sphere. The electrons on the brush gets attracted to the belt; the air molecules in between also breaks down, and all the charges gets spread on the metal sphere.
This electrostatic effect is the reason behind the generation of high voltages in a van de Graaff generator.
Several car manufacturers paint cars using static electricity.
The surface of the car is first prepared and then is placed in a paint booth. Now, electrical charge is given to the paint and it is sprayed into the booth. The car attracts the charged particles and is stuck on the car body. Once the paint dries, it becomes smooth and sticks much better to the car surface.
In several industries and factories, electrostatic precipitators are used to prevent or control the emission of hazardous particles that pollute the air. These devices work based on the principle of static electricity.
The dirt, smoke or harmful particles are given an electric charge. When these pass through the electrodes which are oppositely charged, the particles get attracted to the electrode and hence prevents the atmosphere from getting polluted.
How Static Electricity Is Created: Frequently Asked Questions
Give some commonly observed day to day instances of triboelectric effect.
Triboelectric effect is when rubbing of two materials generates charge in them. Examples of tribolelectric effect that are commonly observed are:
- Rubbing glass with vinyl
- Rubbing a plastic comb with hair
- Rubbing a plastic soda bottle with hair
- Friction due to socks on carpet
- Rubbing a vinyl pipe using a cotton facecloth
Explain briefly about triboelectric series.
Triboelectric effect is commonly observed in insulators. Insulators build up charges. In the triboelectric series, materials at the bottom of the series when rubbed with a material at the top, attains a negative charge. Van de Graff generator is a good example for triboelectric effect.