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What Is Electrical Energy? Examples and Explanation

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Posted by Ashley Robinson | Feb 28, 2021 8:00:00 AM

General Education

 

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Electrical energy is an important concept that helps run the world as we know it. In the U.S. alone, the average family uses 10,649 kilowatthours (kWh) per year, which is enough electrical energy to brew over 120,000 pots of coffee! 

But understanding what electrical energy is and how it works can be tricky. That’s why we’ve put together this article to help enlighten you! (Pardon our dad joke.) 

Keep reading to learn all about electrical energy, including:

  • The definition of electrical energy
  • How electrical energy works
  • If electrical energy is potential or kinetic
  • Electrical energy examples

 By the time you’re finished with this article, you’ll know the essentials of electrical energy and be able to see its influence all around you.

We’ve got a lot to cover, so let’s dive in!

 

via MEME


Danny Zuko's best subject was definitely physics...especially when it comes to the laws of attraction. #DadJoke (Meme/Me.Me)

 

Electrical Energy Definition

So, what is electrical energy? In a nutshell, electrical energy is the energy (both kinetic and potential) in the charged particles of an atom that can be used to apply force and/or do work. That means that electrical energy has the capacity to move an object or cause an action

Electrical energy is all around us in many different forms. Some of the best electrical energy examples are car batteries using electrical energy to power systems, wall outlets transferring electrical energy to charge our phones, and our muscles using electrical energy to contract and relax!

Electrical energy is definitely important for our day-to-day lives, but there are lots of other types of energy out there, too. Thermal energy, chemical energy, nuclear energy, light energy, and sound energy are just some of the other major types of energy. Although there may be some overlap of the types of energy (like a wall outlet providing light to a lamp that produces a small amount of heat), it’s important to note that the types of energy act distinctly from one another, though they may be converted into other types of energy.

 


This quick explainer video on electricity is a great primer on what electrical energy is and how it works. 

 

How Does Electrical Energy Work?

Now that you know what electrical energy is, we’ll cover where electrical energy comes from.

If you’ve studied physics before, you might know that energy can be neither created nor destroyed. Although it might seem like the results of electrical energy come from nowhere, the energy in a bolt of lightning or a jogging session come from a series of changes at the molecular level. It all starts with atoms. 

Atoms contain three main parts: neutrons, protons, and electrons. The nucleus, or the center of the atom, is made up of neutrons and protons. Electrons circle the nucleus in shells. The electron shells kind of look like rings or orbital paths that go around the nucleus. 

 

body-atom-diagram

(AG Caesar/Wikimedia)

 

The number of shells an atom has depends on a lot of things, including the type of atom and whether it’s positively, negatively, or neutrally charged. But here’s the important bit when it comes to electrical energy: the electrons in the shell closest to the nucleus have a strong attraction to the nucleus, but that connection weakens as you move out to the outermost shell. The outermost shell of an atom is known as the valence shell...and the electrons in that shell are known as valence electrons! 

Because the valence electrons are only weakly connected to the atom, they can actually be forced out of their orbits when they come into contact with another atom. These electrons can “jump” from the outer shell of their home atom to the outer shell of the new atom. When this happens, it produces electrical energy. 

So how do you know when an atom is primed to gain or lose electrons to create electrical energy? Just take a look at the valence electrons. An atom can only ever have eight valence electrons in its outer shell, also known as an octet. If an atom has three or fewer valence electrons, it’s more likely to lose electrons to another atom. When an atom loses electrons to the point that its protons outnumber its electrons, it becomes a positively charged cation. 

Likewise, atoms that have an almost full valence shell (with six or seven valence electrons) are more likely to gain electrons in order to have a full octet. When an atom gains electrons to the point where electrons outnumber the atom’s protons, it becomes a negatively charged anion. 

Regardless of whether an atom gains or loses electrons, the act of electron movement from one atom to another results in electrical energy. This electrical energy can be used in the form of electricity to do things like power the appliances in your house or run a pacemaker. But it can also be converted to other kinds of energy, like the thermal energy from a toaster that’s plugged into a wall.

 

body-lightning-electricity-cc0

Think electrical energy and electricity are the same thing? Not quite! Electricity is just one result of electrical energy. 

 

Electric Energy vs Electricity

While these terms sound similar, electric energy and electricity are not the same thing. While all electricity is the result of electric energy, not all electric energy is electricity.

According to Khan Academy, energy is defined as the measurement of an object’s ability to do work. In physics, “work” is the energy to an object in order to move an object As we talked about in the last section, electric energy comes from the movement of electrons between atoms, which creates a transfer of energy...also known as work. This work generates electric energy, which is measured in Joules. 

Keep in mind that electric energy can be converted to all sorts of other kinds of energy, like the thermal energy from a toaster that’s plugged into a wall. That thermal energy creates heat which is what turns your bread into toast! So while electrical energy can become electricity, it doesn’t have to! 

When the electron flow of electrical energy is channeled through a conductor, like a wire, it becomes electricity. This movement of an electric charge is called an electric current (and is measured in Watts). These currents, completed through electrical circuits, can power our TVs, stovetops, and much more, all because the electrical energy was directed towards producing a particular desired action, like lighting up the screen or boiling your water.

 

Is Electrical Energy Potential or Kinetic?

If you’ve studied energy before, you know that energy can fall into two different main categories: potential and kinetic. Potential energy is essentially stored energy. When atoms’ valence electrons are kept from jumping around, that atom is able to hold--and store--potential energy. 

On the other hand, kinetic energy is essentially energy that moves or moves something else. Kinetic energy transfers its energy onto other objects in order to generate force on that object. In kinetic energy, the electrons are free to move between valence shells in order to create electrical energy. Thus, the potential energy stored in that atom is converted to kinetic energy...and ultimately, electrical energy. 

So, is electrical energy potential or kinetic? The answer is both! However, electrical energy cannot be both potential and kinetic at the same time. When you see electrical energy enacting work on another object, it’s kinetic, but right before it was able to do that work, it was potential energy. 

Here’s an example. When you’re charging your phone, the electricity moving from the wall outlet into your phone battery is kinetic energy. But a battery is designed to hold electricity to use later. That held energy is potential energy, which can become kinetic energy when you’re ready to turn your phone on and use it. 

 


Electromagnets--like the one above--work because electricity and magnetism are closely related.
(Amazing Science/Giphy)

 

What Does Electrical Energy Have to Do With Magnetism?

You’ve probably played with a magnet at some point in your life, so you know that magnets are objects that can attract or repel other objects with a magnetic field. 

But what you might not know is that magnetic fields are caused by a moving electrical charge. Magnets have poles, a north pole and a south pole (these are called dipoles). These poles are oppositely charged--so the north pole is positively charged, and the south pole is negatively charged. 

We already know that atoms can be positively and negatively charged, too. It turns out that magnetic fields are generated by charged electrons that are aligned with one another! In this case, the negatively charged atoms and the positively charged atoms are at different poles of a magnet, which creates both an electrical and a magnetic field. 

Because positive and negative charges are a result of electrical energy, that means that magnetism is closely related to systems of electrical energy. In fact, so are most interactions between atoms, which is why we have electromagnetism. Electromagnetism is the interrelated relationships between magnetic and electric fields. 

 


Check out some hair-raising examples of electrical energy below. #AnotherDadJoke
(Gifbin/Giphy)

 

Electrical Energy Examples

You may still be wondering, “What is electrical energy like in the real world?” Never fear! We’ve got four great real-life electrical energy examples so you can learn more about electrical energy in practice.

 

Example 1: A Balloon Stuck to Your Hair

If you’ve ever been to a birthday party, you’ve likely tried the trick where you rub a balloon on your head and to stick it to your hair. When you take the balloon away, your hair will float after the balloon, even while you hold it inches away from your head! Physics students know that this isn’t just magic…it’s static electricity.

Static electricity is one of the kinds of kinetic energy produced by electrical energy. Static electricity happens when two substances are held together by opposing forces. It is called “static” because the attraction holds the two objects together until electrons are allowed to move back to their original places. Using what we’ve learned so far, let’s take a closer look at how this trick works.

We know that, in order for two atoms to attract, they must have opposite charges. But if both the balloon and your hair start out as neutrally charged, how do they come to have opposite charges? Simply put, when you rub the balloon against your hair, some of the free electrons jump from object to object, making your hair have a positive charge and the balloon a negative charge.

When you let go, the balloon is so attracted to your hair that it tries to hold itself in place. If you try to separate the attracted charges, your positively-charged hair will still try to stay attached to the negative balloon by floating upward using that kinetic electrical energy!

However, this attraction won’t last forever. Because the attraction between the balloon and your hair is relatively weak, the molecules of your hair and the balloon will each try to seek equilibrium by restoring their original numbers of electrons, eventually making them lose their charges as they gain or lose the electrons.

 

Example 2: Cardiac Defibrillators

If you’re looking for good electrical examples of both potential and kinetic energy, look no further than the defibrillator. Defibrillators have saved thousands of lives by correcting irregular heartbeats in emergency situations like cardiac arrest. But how do they do it?

Unsurprisingly, defibrillators get their lifesaving abilities from electrical energy. Defibrillators contain a lot of electrical potential energy that is stored in the two plates of the defibrillator’s capacitor. (These are sometimes known as paddles.) One of the plates is negatively charged, while the other is positively charged. 

When these plates are placed at different locations on the body, it creates an electric bolt that jumps between the two plates. The potential energy becomes kinetic energy as the electrons from the positive plate rush to the negative plate. This bolt goes through the human heart and stops its electrical signals within the muscle with the hope that its irregular electrical pattern will restart to normal.

Defibrillators contain extremely powerful electrical energy, so be careful if you ever are around one!

 

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Example 3: Wind Turbines

Often placed in out-of-the-way places, wind turbines turn natural wind into energy that can be used to power our homes, technology, and more. But how does a turbine change something as seemingly non-electrical as the wind into usable, sustainable energy?

At its most basic, wind turbines turn motion energy into electrical energy. While explaining how wind works deserves a blog post of its own, what you need to know is that when wind hits the turbine’s blades, it turns the rotor hub like a windmill. This kinetic energy turns an internal component, called a nacelle, which contains an electrical generator. In turn, this generator converts this energy into electrical energy by forcing electrical charges already present in the generator to move, creating an electrical current...which is also electricity.

Because this movement is channeled through electricity conductors, specifically wires, this flow of charges can continue to larger electrical grids, like homes, neighborhoods, and even cities.

 

Example 4: Batteries in a Kids’ Toy

In the same way that a wind turbine converts one type of energy into another, a battery in a children’s toy converts energy in order to make the toy work. Batteries have two ends, a positive and a negative. It’s important to put the right ends into the right places in the toy, otherwise it won’t work.

The positive end has—you guessed it!—a positive charge, while the negative end has a negative charge. That means that the negative end has a lot more electrons than the positive end, and the battery as a whole is trying to get to equilibrium. The way that they do this is through chemical reactions that start when the batteries are placed inside a toy that’s turned on. 

The positive end can’t simply get to the negative end because of the acid that separates them in the battery’s interior. Instead, the electrons have to go through the entire toy’s circuitry to reach the negative end, allowing a baby doll to cry or a toy helicopter to fly. 

When all the electrons on the positive end have reached equilibrium, there are no more electrons to go through the wiring, meaning that it’s time for new batteries!

 

Common Units of Electrical Energy

While studying the basic electrical energy definition and principles are important, you’ll also need to know some formulas and equations as you continue exploring electrical energy. Many of these formulas use the same symbols to signify particular units.

We’ve included a table of some of the most common units of electrical energy for your reference, as well as what each unit means.

Unit of Measurement
Symbol
Definition
Joule
J
The amount of work being done
Electron volt
eV
The energy exerted on one electron through one volt.
Voltage 
V
The potential difference between two points
Coulomb
C, or Q, or q when used in the same formula as capacitance.
The quantity of electrical charge
Capacitance
C (Be careful, as this is commonly confusing!)
The capacity of a conductor to store electrical potential energy
Ampere
A
Commonly called an “amp,” the ampere is the unit of measurement that measures the strength of a current when in a conductor.
Second
s
Seconds are a time measurement commonly used to determine the strength of other energy units.
Hour
h
Hours are a time measurement commonly used to determine the strength of other energy units.
Megawatt
MW
1,000,000 watts
Kilowatt
kW
1,000 watts
Watt
W
The rate at which energy is producing work

Source: https://www.electronics-tutorials.ws/dccircuits/electrical-energy.html

While there are many more units that you may need in your equations for electrical energy, this list should get you started!

 

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Conclusion: Here’s What to Remember About Electrical Energy

You’ve made it through your crash course on electrical energy, and now you’re ready to tackle any exam or course that will test your electrical physics knowledge. However, if you remember nothing else, keep these in mind in your next electrical energy lesson:

  • The electrical energy definition: the ability to perform work.
  • Electrical energy comes from the attraction or repulsion of negatively and positively-charged molecules.
  • Electrical energy is both potential and kinetic energy.
  • A few electrical energy examples are a defibrillator, a battery, and wind turbines.

We hope you’ve been positively charged with all the information in this blog! Keep studying, and in no time, you’ll be an electrical energy pro. 

 

What's Next? 

Need a little extra help with your Physics formulas? Then this equations cheat sheet is exactly what you're looking for.

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If you're in IB Physics, we've got you covered, too. Here's a breakdown of the course syllabus, and here's our round-up of the best IB Physics study guides out there.

 

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Ashley Robinson
About the Author

Ashley Sufflé Robinson has a Ph.D. in 19th Century English Literature. As a content writer for PrepScholar, Ashley is passionate about giving college-bound students the in-depth information they need to get into the school of their dreams.



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