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1. Getting Started
1. Getting Started
Electricity is all around us powering technology like our cell phones, computers, lights, soldering irons, and air conditioners. Even when you try to escape electricity, it's still at work throughout nature, from the lightning in a thunderstorm to the synapses inside our body. But what exactly is electricity?
Electricity is a natural phenomenon that occurs throughout nature and takes many different forms. It is a form of energy resulting from the existence of differently charged particles (such as electrons or protons), due to atrction forces.
Electricity is made up of moving electrons. They can be observed in nature in the form of lightning, neural transmissions, in eels and even in the small electric arc or blow that one receives when touching a doorknob.
Our goal is to understand how electricity flows from a power source through wires, lighting up LEDs, spinning motors, and powering our communication devices.
why is it so widely used ?
why is it so widely used ?
Electricity is a convenient and clean form of energy that is very commonly used in our everyday lives. It can easily be transformed into other forms of energy, like luminous energy, heat energy, mechanical energy, etc. Situations as simple as switching on or off a light, turning the washing machine on or using a computer are possible thanks to electricity.
Electricity can be treated or studied from two different standpoints (perspectives): as energy transmitted and transformed into another form of energy (Power W and Electrical enenrgy kWh) and the other as the study of the behavior of electrical variables(Voltage V, Current I and Resistenace R) inside the elemets of the circuit.
Electricity is a form of energy that we use it to transform in another type of energy like motion, light, heat, sound...
Aother definition electricity is briefly defined as the flow of electric charges through a conductor.
Electricity is briefly defined as the flow of electric charges thrugh a conductor, but there's so much behind that simple statement. Where do the charges come from? How do we move them? Where do they move to? How does an electric charge cause mechanical motion or make things light up? So many questions! To begin to explain what electricity is we need to zoom way in, beyond the matter and molecules, to the atoms that make up everything we interact with in life.
Static electricity
Static electricity
When a pen is rubbed on a piece of cloth and then placed next to small pieces of paper, those little bits of paper will be attracted to the pen. This is because the pen picks up electrical charges from the cloth and attracts the pieces of paper because they are not electrically charged.
The manifestation of energy associated with electrical charges, both at rest and in movement, is called electrical energy or simply electricity.
Electricity can be obtained from many different sources such as petroleum, wind, the sun or water. It is easy to transport electricity across long distancesand it can be transformed into other forms of energy, such as luminous energy, heat energy, etc. These characteristics make electricity the most commonly used form of energy in our society.
To understand the fundamentals of electricity, we need to begin by focusing in atoms.
An atom is built with a combination of three distinct particles: electrons, protons, and neutrons. Each atom has a center nucleus, where the protons and neutrons are densely packed together. Surrounding the nucleus are a group of orbiting electrons.
Atoms are neutrally charged. The positives forces, protons and negative charges electrons arein equilibrium.
Every atom must have at least one proton in it. The number of protons in an atom is important, because it defines what chemical element the atom represents.
Electrons are critical to the workings of electricity (notice a common theme in their names?) In its most stable, balanced state, an atom will have the same number of electrons as protons. As in the Bohr atom model below, a nucleus with 29 protons (making it a copper atom) is surrounded by an equal number of electrons.
The atom's electrons aren't all forever bound to the atom. The electrons on the outer orbit of the atom are called valence electrons. With enough outside force, a valence electron can escape orbit of the atom and become free. Free electrons allow us to move charge, which is what electricity is all about.
A very simple atom model. It's not to scale but helpful for understanding how an atom is built. A core nucleus of protons and neutrons is surrounded by orbiting electrons.
Electrostatic force
Electrostatic force
Electrostatic force is a force that operates between charges. It states that charges of the same type repel each other, while charges of opposite types are attracted together. Opposites attract, and likes repel.
Electricity: the energy generated by the forces of attraction or repulsion between charged particles.
The amount of force acting on two charges depends on how far they are from each other. The closer two charges get, the greater the force (either pushing together, or pulling away) becomes.
Using enough electrostatic force on the valence electron either pushing it with another negative charge or attracting it with a positive charge we can eject the electron from orbit around the atom creating a free electron.
Now consider a copper wire: matter filled with countless copper atoms. As our free electron is floating in a space between atoms, it's pulled and prodded by surrounding charges in that space. In this chaos the free electron eventually finds a new atom to latch on to; in doing so, the negative charge of that electron ejects another valence electron from the atom. Now a new electron is drifting through free space looking to do the same thing. This chain effect can continue on and on to create a flow of electrons called electric current.
Electrons motion in metalic bonds. The electrons move randomly in all directions.
This changes when a voltage is applied. The electrons move in the same direction.
Materials that do not conduct electricity are called insulators; some examples of insulators are plastic, glass or wood. In these cases, electrons are strongly bonded to the nucleus.
A conductor is a material that allows the flow of electrical current. Conductors are materials that have a high density of free electrons, which can move easily through the material in response to an electric field or difference of potential. Common examples of conductors include metals such as copper, aluminum, and gold. These materials are used extensively in electrical wiring and circuitry due to their ability to efficiently conduct electricity.
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