Electric current

What Is Electricity?

Electricity is the set of phenomena caused by the existence, interaction, and motion of electric charges. It is the energy derived from electric potential energy or kinetic energy.

What is electricity?

This form of energy manifests itself in charged particles' movement on the surface of a conductive material. The charged particles can be electrons, protons, or ions.

There are two points of view to analyze it:

  • From a macroscopic scale: what a person can observe.

  • From a microscopic scale: to observe what is happening, it is necessary to use special devices. The set of things that happen on a tiny scale corresponds to what we can see on a macroscopic scale.

From the macroscopic point of view, by this term, we refer to the electromagnetic force. That is, to all large-scale physical phenomena involving one of the fundamental interactions—especially electrostatic energy.

From a microscopic point of view, these phenomena are due to the interaction between charged particles on a tiny scale, a molecular scale.

Typical macroscopic effects are currents and the attraction or repulsion of charges.

Types of Electricity

There are two kinds:

  • Static. This type is produced by rubbing two or more objects and making friction.

  • Dynamic. It is the flow of charge through a conductor.

Static Electricity

Static electricity is produced by accumulating electrical charges on the surface of a material. It is generally caused by rubbing materials. The result of a build-up of static electricity is that objects can be attracted to each other or even cause a spark to jump from one to the other.

An example is a result of rubbing a balloon with wool. After rubbing the balloon, it remains slightly glued to the hand. The reason this happens is that the electrons in the thread are transferred to the balloon.

The electrons have a negative charge so that the balloon acquires a negative charge higher than the hand's charge. At this time, we can say that the balloon is statically charged. The difference in charges generates an attraction between the balloon and the hand.

Dynamic Electricity

Electric current is the rate of flow of electrons produced by moving electrons. The units to measure its intensity in the SI are amps. Unlike static electricity, it must flow through a conductor.

The current is a measure of the amount of energy transferred over a while. That energy is called the flow of electrons. One of the results of the current is the heating of the conductor.

An electric generator is a device that converts mechanical energy into electrical power. The primary power plants work in the same principle but only changing their source of electric power.

What Is an Electric Charge?

Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. Charges can be positive and negative:

  • Positive charge, usually carried by protons (positive charge).

  • The negative charge which typically carries by electrons.

Similar charges repel each other, and different charges attract each other. An object with no net charge is called neutral.

An object with one charge exerts a force at a certain distance on another item that has another charge. This concept is similar to gravity, which makes one object attract another.

The value of a body's electric charge depends on the number of electrons in excess or deficiency.

What Is an Electric Field?

An electric field is the state of tension that appears in space around an electron or any other object with a positive or negative charge.

This field interferes with other charged objects' fields and causes the joint forces typical of such items.

Electrons motion generate another field where they pass. This new field is called a magnetic field. This field's intensity is directly proportional to the number of moving electrons and the speed at which they move, that is, to the electric current.

Therefore, if a current is passed through a conveniently arranged set of copper wire coils, this wire coil will behave like a steel magnet. This new magnet will be able to attract or repel other similar coils of wire. Winding such a loop on an iron frame will reinforce the produced magnetic field.

With all this, combining several coils of wire around an iron core, free to rotate, can obtain significant substantial mechanical forces. This device is called an electric motor.

Nowadays, these engines operate in all kinds of machinery, from the dentist's delicate exercises to the gigantic machines of modern factories. There can be many electric motors in a house, from the oil boiler to the refrigerator.

Michael Faraday established the basis for the concept of the electromagnetic field in physics. He based his work on his research on the magnetic field around a conductor carrying a direct current.

Types of Current

Two types of current can transmit electrical energy:

  • Alternating current (AC), in which the electrons vibrate but do not move.

  • Direct current (DC), in which the electrons move through the conductor.

Electricity flows in a closed circle, called a circuit.

In a direct current circuit, the electrons always move in the same direction within it. Any battery-powered circuit is an example of this circuit (for example, a magnesium flash or an electrical system in automobiles). Sometimes, however, the current does not remain constant.

Occasionally, numerous electrical circuits regularly reverse the current direction of its flow. In this case, it is an alternating current circuit.

The most common and used electrical circuits are alternating current. The frequency, intensity of the current, and the circuit's voltage must be specified in an alternating current circuit. Frequency measures half the number of times the current changes direction in one second.

Who Discovered Electricity?

Most people credit Benjamin Franklin, a man ahead of his time and one of the most outstanding scientists in human history. Interested in many areas, he discovered and invented many things, including electricity in the mid-18th century.

In 1747 Franklin began his experiments on electricity. He was convinced that storms were electrical phenomena and proposed a reckless method to prove it. One stormy night he flew a kite with a metal tip tied to a silk thread at the end of which was a key, also metal.

Franklin held the kite with another silk thread. When the storm clouds gathered, and the cable began to show the electrical charge as the fibers repelled each other, Franklin put his knuckle near the key, and sparks flew.

Also, he managed to load a bottle of Leyden, a glass container designed to store electrical charges.

Thanks to his studies on electricity, Franklin devised the terms positive and negative electricity, electrical conductor, or battery. He proposed that electricity is a 'single fluid' or 'electric fire' that passes from one body to another in discharge, which led him to enunciate the Principle of Conservation of Electricity. He based his theory on Newton's postulates.

Who Discovered the Electric Light?

On October 22, 1879, Thomas Alva Edison was successful in his attempt to illuminate an incandescent light bulb with electricity.

That first, Thomas Edison light bulb lasted 13½ hours and was the beginning of a process of constant improvement, which has brought us the electric light we enjoy today.

Why Is Electricity Necessary?

Electricity is responsible for transporting energy from where energy is generated to the point where it is used. It allows having access to power in our homes. Likewise, multiple industrial applications work utilizing this source.

This energy transport capacity has become the most widespread means of transport for energy in electricity grids. It is one of the most pervasive means of transportation for information in telecommunications.

How Does Electricity Contribute to Climate Change?

Electricity is the ability to transport energy. Thus, it does not influence climate change. However, it can help reinforce technologies that do affect climate change.

If this form of energy transport did not exist, to heat our homes or to have electricity, we would need to burn coal, oil, or gas. As we know, burning fossil fuels generates greenhouse gases that are harmful to the environment.

On the other hand, it allows us to supply energy generated in renewable energy plants to our homes or the required industrial applications. These renewable energy sources can be photovoltaic solar energy, wind power plants, hydropower, etc.


Published: May 20, 2019
Last review: October 24, 2020