Understand Electricity: A Simple Guide
Confused by how electricity works?
It powers our entire world, yet its inner workings can feel like a mystery.
This guide breaks it down into simple, easy-to-understand concepts.
Electricity is the set of physical phenomena associated with the presence and movement of electric charge.
This flow of tiny particles, usually electrons, through a material is called an electric current.
This current is what powers everything from our lights to our computers.
Now that you have a basic idea, let’s explore what electricity is, where it comes from, and the brilliant minds who helped us harness its power.
How Does Electricity Actually Work?
You flip a switch and a light comes on instantly.
But what is actually happening inside the wires to make that possible?
Let’s look at the basic science behind the power you use every day.
Electricity works through the movement of electric charges, which are most often tiny particles called electrons.
This movement is called an electric current.
This current generates an electric field and can power devices when it flows along a closed path, known as a circuit.
To truly understand how electricity works, we need to start with the smallest building blocks of matter and see how they interact.
From there, we can see how their movement creates the power that runs our modern lives.
The Building Blocks: Atoms and Charges
Everything in the universe is made of tiny particles called atoms.
Inside every atom are even smaller parts, including electrons and protons.
- Protons have a positive electric charge.
- Electrons have an negative electric charge.
By convention, opposites attract, while similar charges repel each other.
This means a positive charge will pull a negative charge toward it, but it will push another positive charge away.
This force of attraction or repulsion is a fundamental aspect of electricity.
The amount of charge an electron or proton has is called the elementary charge, and it is the smallest amount of charge an object can have.
From Flow to Power: Current and Circuits
When electrons are pushed or pulled by an outside force, they can move from one atom to another.
This movement or flow of electric charge is what we call an electric current.
The intensity of this current is measured in amperes.
For this current to do useful work, like lighting a bulb, it needs to flow along a complete, closed path.
This path is called an electric circuit.
A simple circuit has three main parts:
- A source: This provides the energy to push the charges. A battery is a common example.
- A path: This is what the charges flow through. It is usually made of a material that lets electrons move easily.
- A load: This is the device that uses the electricity to do work, such as a resistor, a motor, or a lightbulb.
The Path Matters: Conductors and Insulators
Electrons do not flow easily through all materials.
- Conductors are materials that allow electric charges to move through them with ease. Most metals, like copper and zinc, are excellent conductors. This is why electrical wires are made of metal.
- Insulators are materials where electrons prefer to stay put. They do not allow electric current to flow through them easily. Rubber, glass, and plastic are good insulators, which is why they are often used to cover electrical wires for safety.
Where Does Your Electricity Come From?
We use electricity constantly in our daily lives.
But have you ever stopped to think about the journey that power takes to get to your outlet?
Let’s trace the electricity back to its original sources.
In the United States, electricity is generated from a variety of energy sources.
The main categories are fossil fuels like natural gas and coal, nuclear energy, and renewable energy sources like wind, hydropower, and solar power.
Most of these sources are used to power steam or gas turbines to generate electricity.
Across the U.S., thousands of power plants work around the clock to produce the energy we need.
This electricity then travels through a complex network, or grid, to reach our homes, schools, and businesses.
Let’s look at the different ways this generation happens.
The Major Sources: Fossil Fuels and Nuclear
For many years, the bulk of electricity has come from two main categories: fossil fuels and nuclear power.
- Fossil Fuels: In 2023, fossil fuels accounted for about 60% of all electricity generated in the U.S.. This category includes natural gas, coal, and petroleum. These plants work by burning the fuel to produce heat, which boils water into steam. This high-pressure steam then spins the blades of a turbine, which in turn spins a generator to produce electricity. Natural gas was the single largest source, providing about 43% of U.S. electricity in 2023.
- Nuclear Energy: Nuclear power provided about 18% of the country’s electricity in 2023. Nuclear plants operate in a way that is similar to fossil fuel plants, as they also use steam to turn turbines. However, instead of burning fuel, they use the heat generated from a process called nuclear fission to create steam.
The Growing Force: Renewable Energy
Renewable energy has become an increasingly important part of the U.S. energy mix, growing to about 21% of total utility-scale generation in 2023.
These sources are considered renewable because they come from natural resources that are inexhaustible.
Here is a breakdown of the main renewable sources:
| Renewable Source | Share of U.S. Generation (2023) | How It Works |
| Wind | ~10% | Wind turbines use the force of the wind to spin blades connected to a generator. |
| Hydropower | ~6% | Uses the force of flowing water from dams or rivers to turn a turbine. |
| Solar | ~4% | Photovoltaic (PV) panels convert sunlight directly into electricity. Solar-thermal plants use sunlight to create steam. |
| Biomass & Geothermal | ~1% & <1% | Biomass plants burn organic material for steam. Geothermal plants use steam from the Earth’s natural heat. |
The Delivery System: The Power Grid
After electricity is generated, it doesn’t go straight to your home.
First, it is sent through a complex network called the electric power grid.
This system uses high-voltage transmission lines to carry power over long distances.
Along the way, substations and transformers reduce the voltage to a safer level before it is finally distributed to customers.
What Are the Main Types of Electricity?
You have likely experienced a shock from static on a dry day and you use the electricity from your wall outlets every day.
But are these two phenomena the same thing?
Let’s clarify the main forms of electricity.
The two main types are static electricity and current electricity.
Static electricity is charge that builds up on the surface of an object but does not flow.
A common example is a balloon sticking to your hair after you rub it.
Current electricity is the flow of electric charges through a conductor, and it is what powers our appliances.
While these two types seem very different, they are both based on the same fundamental principles of electric charge.
Understanding their differences is key to understanding how electricity works in different situations, from a surprising spark to the steady power in your home.
Static Electricity: The Stationary Charge
Static electricity refers to an imbalance of electric charge on the surface of an object.
It is usually caused when two different materials are rubbed together, causing electrons to transfer from one to the other.
One object ends up with an excess of electrons (a negative charge), while the other has a shortage of electrons (a positive charge).
Because this charge is “static,” it doesn’t move until it is given a path to do so.
Common examples include:
- Rubbing a balloon on your hair, which causes the balloon to stick because of the charge imbalance.
- The small shock you feel when you touch a metal doorknob after walking across a carpet.
- Lightning is a dramatic, large-scale example of static electricity. Collisions between ice and water particles inside storm clouds build up huge amounts of charge. Eventually, this charge discharges as a giant spark, which we see as lightning.
Current Electricity: Charge in Motion
Current electricity is defined as the movement or flow of electric charge.
Unlike static electricity, the charges are constantly moving.
This is the type of electricity we use to power our homes, schools, and businesses.
There are two forms of electric current:
- Direct Current (DC): In DC, the electric charge flows in only one direction. It is a unidirectional flow from the positive part of a circuit to the negative part. Batteries are the most common source of DC power, and it is used by most electronic devices like your phone and laptop.
- Alternating Current (AC): In AC, the flow of electric charge reverses direction repeatedly. The current pulses back and forth within a conductor without the charge moving any net distance over time. Although the average value of the current is zero, it still delivers energy. AC is the type of electricity supplied by power plants to our homes because it can be transported over long distances more efficiently than DC.
Who Were the Discoverers of Electricity?
We take electricity for granted today.
But its discovery was not the work of a single person.
Instead, it was a long journey of observation and experimentation by many brilliant minds over thousands of years.
The understanding of electricity was a gradual process.
Ancient cultures were aware of shocks from electric fish and the static charge from rubbing amber.
However, it wasn’t until scientists like William Gilbert, Benjamin Franklin, and Michael Faraday began to study it systematically that it evolved from a mere curiosity into a powerful science.
The story of electricity’s discovery is a perfect example of how scientific knowledge is built over time, with each generation adding to the work of those who came before.
Let’s look at some of the key milestones and people on this long road of discovery.
Ancient Observations
Long before electricity was understood, people were aware of its effects.
- Ancient Egyptian texts from as early as 2750 BCE described the shocks from electric fish, calling them the “protectors” of other fish.
- Around 600 BCE, the ancient Greek philosopher Thales of Miletus made some of the first recorded observations of static electricity. He noted that if you rubbed a piece of amber with fur, it would attract light objects like feathers. He mistakenly thought this was a magnetic effect, but it was the beginning of the formal study of the phenomenon.
The Scientific Revolution Begins
For centuries, electricity remained little more than a curiosity.
That began to change in the 17th and 18th centuries.
- In 1600, the English scientist William Gilbert made a careful study of both electricity and magnetism. He was the first to distinguish the lodestone effect from the static electricity produced by rubbing amber. He coined the Neo-Latin word electricus (meaning “of amber”) to describe the property of attraction after being rubbed, which gave us the modern words “electric” and “electricity”.
- In the 18th century, Benjamin Franklin conducted extensive research into electricity. He is famous for his dangerous kite experiment in 1752, where he flew a kite in a storm to prove that lightning was electrical in nature. He also came up with the idea of positive and negative charges to explain how devices like the Leyden jar stored charge.
The 19th Century: The Age of Electromagnetism
The 19th century saw rapid progress that finally unlocked electricity’s practical potential.
- In 1800, Alessandro Volta invented the voltaic pile, which was the first true battery. This gave scientists a reliable source of continuous electric current for the first time.
- In 1820, Hans Christian Ørsted made a landmark discovery when he saw that the current in a wire could deflect a magnetic compass needle. This showed a direct link between electricity and magnetism.
- Michael Faraday, a contemporary of Ørsted, made some of the most important contributions. In 1821, he invented the first electric motor. Then, in 1831, he discovered electromagnetic induction—the principle that a changing magnetic field can induce an electric current. This discovery led him to invent the first electrical generator. Faraday’s work laid the foundation for nearly all modern electric motor and generator technology.
Are Renewables the Future of Electricity?
Our world faces significant challenges from our reliance on traditional energy sources.
This has led many to ask if there is a cleaner, more sustainable way to power our future.
All signs point to renewable energy.
Renewable energy is a rapidly growing share of electricity generation in the U.S., accounting for about 21% of utility-scale power in 2023.
With advancing technology and a global push for cleaner energy to combat pollution from fossil fuels, sources like wind and solar are positioned to be a critical part of the future of electricity.
The transition to renewable energy is not just a trend; it’s a fundamental shift in how we produce and consume power.
While there are challenges to overcome, the advantages of a cleaner energy system are driving innovation and investment around the world.
The Problem with Traditional Sources
For over a century, our electricity has primarily come from burning fossil fuels like coal and natural gas.
While effective, these sources have significant drawbacks.
- Limited Resources: Fossil fuels are non-renewable, meaning they are finite resources that will eventually run out. They are also often found in specific parts of the world, making access a geopolitical issue.
- Environmental Impact: The combustion of fossil fuels is a leading source of air pollution and greenhouse gas emissions. They release sulfur dioxide (SO2) and nitrogen oxides (NOX), which can cause acid rain and fine particulate matter that is harmful to human health. They also produce carbon dioxide, a major driver of climate change.
The Rise of Renewable Solutions
Renewable energy comes from natural sources that are inexhaustible, such as the sun, wind, and water.
This makes them a more sustainable long-term solution.
In the United States, the growth of renewable energy has been significant, rising from about 12% of utility-scale generation in 1990 to 21% in 2023.
The leading renewable sources in the U.S. are:
- Wind Power: In 2023, wind was the largest source of renewable electricity, providing about 10% of the total U.S. supply.
- Hydropower: For many years the largest renewable source, hydropower now sits second, generating about 6% of U.S. electricity.
- Solar Power: Solar is one of the fastest-growing sources, accounting for about 4% of total generation in 2023, not including small-scale rooftop systems.
Challenges and the Path Forward
While the future of renewables is bright, there are challenges to address.
- Intermittency: Some of the most promising renewable sources, like solar and wind, are not available 24/7. They are dependent on weather conditions, which can make them unstable.
- Energy Storage: To overcome intermittency, we need effective ways to store excess energy generated during sunny or windy periods for use when it’s dark or calm. Energy storage technologies, like large-scale batteries, are playing an increasingly important role in making the grid more reliable as more renewables are added.
Despite these hurdles, the momentum is clear.
With continued innovation in technology and infrastructure, renewable energy is set to be the foundation of a cleaner, more sustainable global power system.
Conclusion
Electricity is the simple flow of electrons, a fundamental force of nature.
It comes from diverse sources, with sustainable renewables on the rise.
Understanding these basics helps us appreciate the power that drives our modern world.
Frequently Asked Questions (FAQs)
What is the difference between a watt, a volt, and an amp?
An amp (ampere) measures the flow rate of electric current.
A volt measures the electric potential or pressure.
A watt is the unit of power, calculated by multiplying volts by amps.
How fast does electricity travel?
The electric field that drives the current travels at nearly the speed of light.
The electrons themselves, however, move much more slowly, often only fractions of a millimeter per second.
Why do homes use AC instead of DC power?
Alternating Current (AC) is used for homes because its voltage can be easily changed with transformers.
This allows power to be transmitted over long distances at high voltage with less energy loss.
Can electricity be stored?
Yes, electricity can be stored as chemical energy in devices like batteries and rechargeable cells.
It can also be stored in the electric field of a capacitor.
What is an electric field?
An electric field is a region around a charged particle where a force would be exerted on other charges.
It is a vector field, meaning it has both strength and direction at every point.
Is electricity a primary or secondary source of energy?
Electricity is a secondary energy source.
This means it is produced by converting primary sources like fossil fuels, nuclear energy, or renewable resources like wind and solar power.
