At some point, we’ve probably all slumped on the sofa and thought: “Today, I’ve just got no energy.”  

Psychologically, that statement may be correct. But scientifically, it’s wrong. Why? Because any person relaxing on the couch has potential energy, whether they know it or not.  

Governments often talk about the potential of renewable energy systems like solar and wind. Is that the same as potential energy? 

This guide explains potential energy, its different forms, and how to spot it in everyday life to help you understand the world of energy that surrounds you. 

Introduction: What Is Potential Energy?

Let’s first start with energy, which is defined as a system’s ability to do “work.” This work could be riding a bike or cooking food. In one sense, energy is the amount of work or effort required to do something. 

This leads us to potential energy. The concept of potential energy is the capacity or ability something has to do this work. We also call this stored energy. Potential energy is often known as the energy of position, or where things are, and how their positions affect each other. 

Suppose we’re sitting stationary on a bike on a flat road. In that case, our bodies have a certain amount of potential energy to power that bike. Now imagine sitting on that bike atop a mountain with a beautiful asphalt road to descend. The bike and its occupant, by virtue of their position, have much more potential energy and can rapidly do more “work” descending the slope. 

Therefore, potential energy is an object’s stored energy that exists because of that object’s position – us on a bike on a mountain top. That stored energy is released when our object’s position or state changes, e.g., whizzing down the hill on the bike. 

Finally, there are two primary energy forms of which we need to be aware: potential energy and kinetic energy. 

Kinetic energy is the energy of motion or movement of an object. Keeping with our bike scenario, we release its potential energy as we descend the hill, converting stored energy into motion or kinetic energy. 

Who Discovered Potential Energy?

Scottish engineer and physicist William Rankine coined the phrase “potential energy” in the 19th century. The first law of thermodynamics states that a system’s energy remains the same, even if the energy has been transformed from one energy type to another, e.g., from potential to kinetic energy. 

So, an object’s potential energy can be converted into the equivalent amount of kinetic energy. The process can also be reversed so kinetic energy becomes potential energy. 

This theorem is the same as Isaac Newton’s law of conservation of energy, which proposes that energy within a system cannot be created or destroyed. It states that energy can only be converted from one form to another; a system’s total energy values remain constant. These are essential concepts to remember as we deepen our understanding of potential energy. 

What Are the Different Forms of Potential Energy?

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We know potential energy is position-relative energy, which is also called stored energy. Curiously, there are different types of potential energy. Objects can have potential energy in several ways. 

The two types of potential energy are gravitational potential energy and elastic potential energy. While both are potential energy, their stored energy can seem very different. 

What Is Gravitational Potential Energy?

On Earth, there’s a force of gravity; it keeps us pinned to the floor. The Earth’s gravitational field is also a key player in the potential energy of an object. 

Known as gravitational potential energy, an object’s position within a gravitation field affects how much energy that object possesses. Think about a roller coaster. These heavy vehicles use gravitational potential energy to provide the thrills and spills as they zoom down their tracks. 

Let’s imagine we’re boarding a 12-carriage roller coaster that climbs 200 feet above the ground; it has much more potential energy than when it’s stationary at ground level. The object’s height affects how much potential energy it contains. 

As the carriages stop at their apex, the roller coaster’s gravitational potential energy is immense. Once the roller coaster starts to whoosh around its track, that gravitational potential energy changes into kinetic energy, the energy of movement. 

The roller coaster’s mass also affects its gravitational potential energy. Let’s uncouple 11 of those 12 carriages and send a small, one-cart roller coaster up the 200-foot-high track. The mass of the object is smaller than the 12-carriage roller coaster. It still has gravitational potential energy, but not as much as the larger roller coaster. 

Gravitational potential energy helps explain why larger objects higher off the ground have more potential energy than smaller objects closer to the surface of the Earth. The gravitational force acting upon objects gives them stored gravitational energy. 

Alternatively, think about yourself and your position on Earth. Lying flat in your yard or garden means you have little gravitational potential energy. Now imagine you are gazing over New York from the rooftop terrace of the Chrysler building. Suddenly, you have a lot more potential energy if you were to fall. Next, imagine you’re in a hot air balloon, a mile up. Your potential energy has increased again, despite your body remaining the same. 

What Are Examples of Gravitational Potential Energy?

Examples of gravitational potential energy include: 

• A glass on a table before it falls 
• A stationary bike or vehicle at the top of a hill or mountain 
• The water held behind a reservoir dam 
• A weightlifter is holding weights above their head 
• A ski-jumper at the top of the jump, waiting to ski down 

What Is Elastic Potential Energy?

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Elastic potential energy stores potential energy in objects when we stretch, squash, or compress them. This stored energy is released when we stop exerting a force upon them. 

For example, a string and bow change shape when an archer pulls back their bow. The energy they used to draw the bow is stored within its new form. Once the archer releases the bow’s string, that stored elastic potential energy changes into kinetic energy as the bow returns to its original shape. The arrow also takes some of that elastic potential energy to power its journey. 

You can recreate this idea at home by stretching and flicking rubber bands. A dormant rubber band has some potential energy. Stretch it, and that “work” has given it greater elastic potential energy. Flick the rubber band away, and it returns to its standard shape but also releases kinetic (movement) energy and perhaps even some sound energy. 

What Are Examples of Elastic Potential Energy?

Examples of elastic potential energy include: 

• A stretched rubber band 
• A wind-up toy 
• A compressed coil or spring — springs with a higher spring constant are harder to stretch 
• A trampoline 
• A squash ball 

What Are All the Forms of Potential Energy?

There are several examples of potential energy, some of which we’ve already covered. Here’s a quick rundown of potential energy forms. 

• Gravitational potential energy: Our roller coaster at the top of the tracks and our bike atop a hill have the potential to move toward the Earth. 
• Elastic potential energy: Stretching a rubber band or an archer pulling back their bow creates stored elastic potential energy. This turns into kinetic energy when we return the object to its normal state, e.g., by releasing the bow or rubber band. 
• Chemical potential energy: Chemical reactions occur when we eat and digest food. Our bodies break down the food’s molecules, releasing chemical energy we convert into energy. 
• Nuclear energy: Splitting atoms releases their potential energy, which we harness as atomic energy. 
• Mechanical energy: This energy can be kinetic or potential. Our bike uses mechanical energy to move. It also has potential mechanical energy when it’s stationary atop the hill. Mechanical energy is the sum of its kinetic and potential energy. 
• Magnetic potential energy: Some objects, such as metal spoons, respond or move when subjected to magnets. 

Is Thermal Energy Potential or Kinetic Energy?

Heat energy, or thermal energy, is a form of both kinetic and potential energy. Indeed, some 90% of the energy we use comes to us from the sun. 

Plants photosynthesize sunlight to grow, often into crops we harvest and eat. The sun also warms the oceans and the surface of the Earth and helps create winds. Solar panels and wind turbines capture some of this energy. 

Thermal energy is both potential and kinetic energy. Atoms have kinetic energy as electrons move around their nuclei, held by an electric field. This is kinetic energy. 

Thermal potential energy is stored between the atom’s protons, electrons, and neutrons. We can release the potential energy of atoms by causing collisions between electrons and releasing electricity. However, the released electricity is kinetic energy. 

How Do We Measure Potential Energy?

We measure the potential energy of an object via the International System of Units (SI unit) called joules (J). One joule is equivalent to the work required for a person to raise an object that weighs one newton to a height of one meter. People often cite an average-sized apple as a good example of an object weighing a newton. One newton is around 100 grams (0.22 lbs).We measure the potential energy of an object via the International System of Units (SI unit) called joules (J). One joule is roughly equivalent to the work required for a person to raise an apple to a height of one meter.  

Moving that apple takes one newton of kinetic energy, and the apple, now one meter above the ground, has one newton of potential energy. 

How Do We Calculate Potential Energy?

Calculating potential energy requires understanding a bit of high school physics vocabulary: 

• Mass (m): Take the object’s mass measured in kilograms 
• Gravity (g): This is the acceleration of the object due to the force of gravity 
• Height (h): How far from the ground the object is, in meters 

The equation for calculating potential energy is, therefore: 

Potential Energy = mgh (mass x gravity x height). 

Let’s take a one-kilogram bag of flour (2.2 lbs) and suspend it two kilometers off the ground. Now, let’s lift a 4,000kg (818 lbs) car and lift it 10 centimeters (4 inches) from the ground. Which has the most potential energy? 

The flour has 19,613.3 joules of potential energy. 

The car has 3,922.66 joules of potential energy. 

Surprised? This potential energy calculator can help you play around with the potential energy of objects. It’s fascinating to see how the distance between Earth and objects is a significant contributor to an object’s potential energy. 

Unlocking the Possibilities of Potential Energy

Energy surrounds our daily lives and is a sizable part of our language. Office managers may talk about good energy, or we might moan about lacking energy. To some, energy may conjure images of athletes and performance. But the more sedate-sounding potential energy is equally important. 

We don’t lose energy within systems. It just converts into something else. Potential energy is about what objects may do under the right circumstances. As one of the two primary energy types, potential energy helps us understand how an object’s position and mass affect the energy it contains. 

Promisingly, potential energy can be converted into other useful energy types for humankind. This is especially true and vital in the battle against climate change and the rise of renewable energy. 

Besides helping crops and animals survive, solar panels can harness the sun’s power to produce electricity. Dams hold back vast reserves of potential energy. The water, once released, can spin turbines to create hydropower electricity.  

Humankind is starting to unlock the vast potential energy sources on Earth and in the solar system. Understanding that potential energy can power our homes, businesses, and lives indicates its importance. 

Brought to you by energysavings.com

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