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Static Electricity

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Static Electricity

Did you know that the Ancient Greek name for amber is elektron? What does that have to do with electricity? Back in 600 BC the Greek mathematician Thales noticed that a piece of amber rubbed with wool attracts dust crumbs and cat hair. This is perhaps the earliest recorded example of an observation of the effects of static electricity. Static electricity is caused by a disproportionate amount of negative and positive electric charges inside or on the surface of a substance. The fact that objects rubbing against each other sometimes attract and sometimes repel other objects lead Thales and the philosophers of that period to realize that there could be two kinds of electric charge.

The naming of the electric charges discovered in 600 BC took place approximately 2300 years later. The positive and negative names of electric charges were given by Benjamin Franklin in the 1700s. Franklin suggested that the charge of the plastic rod be called negative and the charge of the glass rod positive. In the following years, in the light of developments in physics, the nature of electric charges has been learned definitively.

Static Electricity A drawing of Benjamin Franklin in 1767 StudySmarterBenjamin Franklin in 1767, Wikimedia Commons

Atoms, which are the basic building blocks of ordinary matter; consist of protons, neutrons, and electrons. Protons and neutrons that make up the nucleus are of interest to nuclear physics. A large amount of energy is required to separate these particles from each other. The situation is different for electrons circulating around the nucleus. It is much easier to remove an electron from an atom or to take an electron from an atom, compared to removing a proton from the atomic nucleus.

Atoms, and therefore matter made up of atoms, tend to be neutral. The atom balances the positivelycharged protons in the nucleus with negativelycharged electrons that orbit the nucleus. An imbalance in electric charge occurs when the number of electrons is more or less than the number of protons. If the number of electrons is more than the number of protons, the charge is negative, and if it is less, the charge is positive. The SI unit of electric charge is Coulomb. The smallest charge found in nature is the charge of the electron. Therefore, an electron charge is defined as an elementary charge or a unit charge.

Static Electricity Examples

The gain or loss of electrons by an atom is called charging. Atoms can gain or lose electrons in different ways. As a result, substances can be electrically charged in different ways.

When neutral (uncharged) objects are brought close to each other, no attraction or repulsion is observed.

Static Electricity Diagram showing how Uncharged objects do not attract or repel each other StudySmarterWhen uncharged objects are brought near each other, they do not attract or repel one another, StudySmarter Originals

Electron exchange takes place between the objects that are rubbed against each other. While an excess negative charge occurs in the object that receives electrons, the negative charge decreases in the object that donates electrons. An excess positive charge occurs in the electron donor body, and an excess negative charge occurs in the electron acceptor body. As in the example that uses wool fabric and a plastic rod, the electron donor object is positively charged, and the receiving object is negatively charged. Objects charged by friction are charged with equal and opposite electric charges. The electron-accepting object is charged with acharge, while the electron-donating object is charged with acharge. The sum of the charges before and after the rubbing of the objects is equal due to the conservation of charge.

Electrostatic forces are non-contact forces. When two plastic rods rub against a piece of wool or two glass rods rubbed with silk cloth are brought closer together, the rods repel each other. This experiment shows that objects charged with the same electric charge repel each other.

Static Electricity Diagram showing Plastic rods rubbed with wool fabric and glass rods rubbed with silk fabric repelling each other StudySmarterWhen two plastic rods rub against a piece of wool or two glass rods rubbed with silk cloth are brought closer together, the rods repel each other, StudySmarter Originals

When the plastic rod that has been rubbed against the wool fabric and the glass rod that's been rubbed against the silk fabric are brought closer together, they attract each other.

Static Electricity Diagram showing how Plastic rod and glass rod attract each other StudySmarterPlastic rods and glass rods attract each other when they are rubbed on wool and silk fabric respectively. StudySmarter Originals

A similar phenomenon is observed when rubbing together wool fabric and a plastic rod, or silk fabric and a glass rod. This shows that objects charged with opposite electric charges attract each other. Due to the repulsive force and the attractive force exerted by the objects on each other, we can be sure that two types of charge must exist.

Static Electricity Diagram showing the Attraction between fabrics and rods StudySmarterObjects charged with opposite electric charges attract each other, StudySmarter Originals

The result of this experiment can be summarized as follows: Charged objects with the same electric charge repel each other, and charged objects with opposite electric charges attract each other.

Uses of Static Electricity

Static electricity is a part of our daily lives. Static electricity is used for pollution control, air cleaning, and the development of technological devices. For example, in photocopying, air filtering for factories, car painting, and mobile phones, static electricity can be used.

Uses of Static Electricity: Pollution control

One particular use of static electricity is to use it to control levels of pollutive particulate matter which could be harmful to humans or more broadly to the natural environment. Two applications of this particular use of static electricity for pollution control are explained below.

Uses of Static Electricity: Electrostatic precipitators

Electrostatic precipitators are one example of the varied uses of static electricity that can be used for pollution control via the application of static charge to attract the particles in the air and collect them. Many power plants use fossil fuels like coal and oil to generate electricity. When these fuels burn, they emit smoke. Smoke contains microscopic solid particles, such as unreacted carbon, which can cause structural damage and respiratory problems. To avoid this, the smoke from waste gases is eliminated before they exit the chimneys. This work necessitates the use of an electrostatic precipitator.

Static Electricity A diagram of a Electrostatic precipitator StudySmarterThe electrostatic precipitator removes tiny particles from the air by forcing them to become charged then attracted to metal plates. Wikimedia Commons

Uses of Static Electricity: Air fresheners

Air may be purified using static electricity. Static electricity is used in air purifiers to change the charges in dust particles so that they attach to a plate or filter of the purifier that has the opposite charge as the dust. These charged particles are drawn to a plate on the device with the opposite charge and attached to it.

Static Electricity An Air refreshener StudySmarterStatic electricity is used in air purifiers to change the charges in dust particles so that they attach to a plate or filter of the purifier that has the opposite charge as the dust, Wikimedia Commons

Uses of Static Electricity: Photocopiers

In photocopiers, a drum or belt is coated with a layer of photoconductive material. When light is incident on a photoconductive substance it will begin to conduct electricity. When a copier shines light onto a piece of paper on the glass surface, static electricity projects a pattern of the image onto the positively charged photoreceptive drum below. When light reflects from blank spaces on the page, it strikes the drum, neutralizing the charged particles that coat the drum's surface. Positive charges are only left on the paper when there are dark spots that do not reflect light. Negatively charged toner is attracted to these positive charges. The toner is then transferred to a positively charged sheet of paper and fused together.

Static Electricity A Printer StudySmarterA printer is an example of the many and varied uses of static electricity in our daily lives, Wikimedia Commons

Electrostatic painting

Electrostatic painting processes are also known as powder painting among the general public. Car bodies are most often painted using electrostatic painting techniques. The principle that opposite charges attract each other is the basic concept behind this process. Electrically charged coloured powder particles adhere to the surface to be painted electrically and stick to the surface completely due to the subsequent firing processes.

Static Electricity A worker painting a car StudySmarterElectrostatic painting is based on the principle of static electricity, Wikimedia Commons

Uses of Static Electricity: Mobile phones

Most smartphones use capacitive touch screens, which are made of materials such as copper or indium tin oxide and store electrical charges in an electrostatic grid of tiny wires, each thinner than a human hair. When a finger touches the screen, a small amount of electrical charge is transferred from the finger to complete the circuit, resulting in a voltage drop at that location. The program analyses the location of the voltage drop before taking a particular preprogrammed action.

Static Electricity Mobile phone StudySmarterA smartphone with a touch screen is also an example of the uses of static electricity, Wikimedia Commons

Dangers of Static Electricity

In tankers carrying flammable liquids, static electricity charge accumulates due to the agitation of the liquid in the tank caused by movement as well as friction with the surrounding air. It is necessary to use a grounding chain in order to prevent this static electricity charge from reaching dangerous levels. The grounding chain allows the built-up static electricity to discharge safely into the ground.

Static Electricity Truck with flammable liquid StudySmarterA truck carrying flammable liquid can be very dangerous if not taken care of properly. That's why you can see a warning signs indiciating that you shouldn't smoke cigarretes or light flames within the vicinity of the tanker. Wikimedia Commons

Dangers of Static Electricity: Bolts of Lightning

Particles within clouds are charged as a result of collision and friction. These particles cause the upper part of the cloud to acquire a purely positive charge and the lower parts of the cloud to become negatively charged. As a result, the soil under the clouds is charged with the opposite charge; that is, positively. The separation of negative charges in the clouds and positive charges on the ground continues for a period of time. The insulating air between the cloud and the ground begins to become conductive, and as the potential difference between the cloud and the ground increases, it becomes easier for a current to pierce the air. With the puncture of the air, the high voltage in the cloud is discharged to the ground. A current between 2,000 and 200,000 amperes flows in these lightning discharges.

Dangers of Static Electricity: Aircrafts

Electricity on the outside of aeroplanes is formed in 3 different ways. Electricity generated by a lightning strike during flight, static electricity generated by friction as the aircraft passes through snow, ice, hail, or dust clouds, and static electricity generated by electronic devices. This static electricity generated on the aircraft is distributed by the pointed metal protrusions on the wingtips of the aircraft. If static electricity circulating in the fuselage of the aircraft was to be momentarily released into the air, it could explode due to the severe discharges that may occur while the aircraft is landing.

Static Electricity A struck plane StudySmarterIf static electricity circulating in the fuselage of the aircraft was to be momentarily released into the air, it could explode due to the severe discharges that may occur while the aircrafts landing, Pixabay.

Static Electricity in the Body

Electric shocks in the body can be caused by the sudden exposure of the body to electricity. When touching an object or making hand contact with someone, crackling sounds are sometimes heard and a sharp 'jolt' can be felt. This is a situation that almost everyone experiences at some point in their lives. Sometimes when shaking hands with someone and sometimes when a door handle is grasped, crackling sounds are heard and the body experiences a momentary electric shock. The excess static electricity accumulated in the body is discharged, causing a feeling of instant electric shock in the persons body.

Static Electricity A kid with his hair up because of static electricity StudySmarterDue to static electricity, a repulsive force occurs, and the boy's hair stands out straight away from the head, Wikimedia Commons

How to Discharge Static Electricity in the Body?

The person can get rid of the static electricity in their body by stepping on clean soil with bare feet.

Static Electricity - Key takeaways

  • Static electricity is defined as the disproportion of electric charges inside or on the surface of a substance.

  • A build-up of electric charge occurs when the number of negative charges is more or less than the number of positive charges, or vice versa. If the number of negative charges is more than the number of positive charges, the charge is negative, and if it is less, the charge is positive.

  • The SI unit of the electric charge is the Coulomb (C).

  • The gain or loss of electrons by a material is called charging.

  • When uncharged (neutral) objects are brought close to each other, no attraction or repulsion is observed.

  • Electron exchange takes place between objects that are rubbed against each other.

  • Objects charged by friction are charged with equal and opposite electric charges. The electron-accepting object is charged with a -q charge, while the electron-donating object is charged with a +q charge.

  • Objects charged with opposite electric charges attract each other, and objects charged the same charge repel each other.

  • Static electricity is generally used in photocopying, air filters (especially electrostatic precipitators), automotive paints, paint sprays, theatres, operating rooms, dust testing and printers.

Frequently Asked Questions about Static Electricity

Static electricity is defined as the build up of electric charges inside or on the surface of a substance. 

A build up of electric charge on the surface of an object- causes static electricity.

The most effective way to remove static electricity from the body is to take a bath. Also, the person can get rid of the static electricity in their body by stepping on clean soil with bare feet. 

Electrostatic forces are non-contact forces.


Rubbing a balloon on your shirt or a wool surface before holding it close to your hair will cause your hair to be attracted to the balloon. This occurs because static electricity builds up on the surface of the balloon. This negative charge creates an electric field which repels the electrons in your hair away from the balloon, causing a net polarisation in your hair and a resulting attraction between your hair and the balloon.

Final Static Electricity Quiz

Question

What is charging?

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Answer

The gain or loss of electric charge by a material is called charging.

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Question

What is the smallest quantity of charge found in nature?

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Answer

The elementary electric charge, equal to the electric charge of an electron or a proton.

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Question

How do objects become electrically charged?

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Answer

Objects become charged when the total number of positive charges on the object is greater than the totsal number of negative charges or vice versa. If the number of electrons is more than the number of protons, the charge is negative, and if it is less, the charge is positive.  

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Question

What happens when uncharged objects are brought close to each other?

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Answer

When uncharged (neutral) objects are brought close to each other, no push or pull of either objects is observed.

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Question

Which experiment shows that objects charged with the same electric charge repel each other?


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Answer

When two plastic rods rubbed against a piece of wool or two glass rods rubbed with silk cloth are brought closer together, the rods repel each other.  

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Question

Objects electrified by friction are charged with equal and opposite electric charge. (True/False)


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Answer

True

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Question

What happens when the plastic rod rubbed on the wool fabric and the glass rod rubbed on the silk fabric are brought closer together?  


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Answer

They attract each other  

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Question

Electrostatic forces are contact forces. (True/False)


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Answer

False. Electrostatic forces are non-contact forces.


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Question

What are the examples of uses of static electricity?

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Answer

Static electricity is generally used in photocopying, air filters (especially electrostatic precipitators), automotive paints, paint sprays, theatres, operating rooms, dust testing and printers.


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Question

How is static electricity used in smokestacks?

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Answer

Static electricity is used by factories to minimize pollution from their smokestacks. They charge the smoke with electricity. The majority of the smoke particles attach to electrodes with the opposite charge as they pass by them.

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Question

What is an example of a danger of static electricity?

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Answer

In tankers carrying flammable liquids, static electricity charge accumulates due to the agitation of the liquid in the tank caused by the movement of the tanker as well as friction with the air. It is necessary to use a grounding chain in order to prevent this static electricity charge from reaching dangerous levels. 




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Question

What's the definition of an electric field?

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Answer

The electric field is defined as the electrical force acting on a unit electric charge. 

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The magnitude of the electric field is directly proportional to the magnitude of the charge. (True/False)


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Answer

True

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The magnitude of the electric field for a point charge is proportional to the distance. (True/False)


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False. the magnitude of the electric field decreases with distance for point charges.

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Question

The direction of the electric field generated by a positive charge is outward while by a negative charge it is towards the charge.  (True/False)


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True

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The electric field lines extend from positive charge to infinity and from infinity to negative charge. (True/False)


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True

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Electric field lines may cross each other. (True/False)

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False. They never cross each other.

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The density of the electric field lines increases with the magnitude of the electric field. (True/False) 

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True

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Electric field lines from a point charge extend symmetrically in three dimensions. (True/False)  


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True

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Question

How are photocopiers related to static electricity?

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Answer

Photocopiers also use static electricity by charging ink to stick it to the paper.


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How is powder painting related to static electricity?

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Answer

Electrostatic painting processes, which are chemical systems in paint processes, are also known as powder painting among the public. Generally, automobile bodies are also painted with this system. The principle that opposite charges attract each other is the basic system of this process. Accordingly, the electrically charged colored powder particles adhere to the surface to be painted electrically and combine with the surface completely with the subsequent firing processes. 

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Question

Any charged particle in an electric field experiences an electrostatic force. (True/False) 

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Answer

True 

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Question

How to check how electric field lines form around positive or negative charges?


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Answer

By approaching the electric field with a positive test charge and seeing if they attract or repel each other.  

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Question

When the +q0 test charge approaches the fixed point +q charge, it experiences a force that attracts it to the +q charge.  (True/False)  


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False.  

It experiences a force that is pushing it away. 

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What is the unit of the electric field?

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Answer

Newtons per Coulomb N/C is the SI unit of electric field strength.

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What is the relationship between sparking and the electric field?

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Answer

Charges may be forced through insulators like air if the field is strong enough, resulting in a spark.

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In which direction do the arrows on electric field lines point?

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Answer

From positive charge to negative charge

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Why does the electric field line formed by a positive charge occur outwards?

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Answer

When the +q0 test charge approaches the fixed point +q charge, it experiences a force that pushes it away from the +q charge. The closer the two charges are to each other, the stronger the magnitude of the force acting between them. The reason for this effect, which cannot be observed without the +q0 charge, is due to the electric field produced by +q. 

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Question

Please explain how mobile phones are related to static electricity.

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Answer

Most smartphones use capacitive touch screens, which are made of materials such as copper or indium tin oxide and store electrical charges in an electrostatic grid of tiny wires, each thinner than a human hair. When a finger touches the screen, a little electrical charge is transferred from the finger to complete the circuit, resulting in a voltage drop at that location. The program analyses the location of the voltage drop and then takes the appropriate action. 

Show question

Question

Why do you feel an instant electric shock when you shake hands with someone?

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Answer

The excess static electricity accumulated in the body is discharged, causing a feeling of instant electric shock in the person's body.  

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