Have you ever wondered how your blender works? Or even how billiards players manage to hit a ball from across the table and into a pocket?
The answer is energy transformation.
Everything in our world—and our universe— occurs through energy transformation. Energy and the ability to convert it between types is the reason things work the way they do. It’s the reason our universe exists the way it does.
Energy transformation is an incredible process, and not only is it happening all around you, but you can slow down and see it if you look close enough. We’ll show you how this thermodynamic process works, explain what it means for the universe, and give you a few ideas for exploring and understanding it with simple, real-world experiments.
What is Energy Transformation?
Energy transformation occurs when a type of energy moves from its original form to a different form.
It happens all around you, all day and every day. Most of your life depends on the transformation of energy.
When you wake up, your coffee maker transforms electricity into thermal energy to heat and prepare your morning coffee.
Do you start the day with a smoothie instead? You still use energy transformation. Your blender uses electricity and turns it into mechanical energy to chop up your fruit and turn it into liquid.
Your body even uses energy. It converts chemical energy from the calories in our food into the energy that allows us to think, breathe, and move. Without energy transformation, you simply wouldn’t exist.
Energy Transformation Relies on the Law of Conservation of Energy
Why does energy transform all around us every day? It all comes back to one of the principal laws of physics: the law of conservation of energy.
The law of the conservation of energy says that within a closed system, energy is neither created nor destroyed. Instead, it continually transforms or changes from one form to another.
Essentially, the amount of energy in a system is always at a constant. There’s never too much or too little. It changes according to what the system demands and turns back again.
That applies to closed systems, like the universe. However, the components within it, like the human body, are open systems, which means we can exchange, gain, and lose energy.
There are some caveats to the law because not all systems are equal. For example, conservation of energy doesn’t feature a definition within curved spacetimes.
How does it work in the world we are most familiar with? Think of it like this. If you play pool, you aim to hit the cue ball at a speed and angle to cause your other pool balls to go into the appropriate pocket. You transfer the kinetic energy from your pool cue to the cue ball and rely on the collision between the other balls to move them without physically touching them yourself.
What is Energy?
To understand energy transformation, we also need to understand energy itself.
A system has energy if it can do work. The word energy comes from “energeia,” an Ancient Greek word first defined by Aristotle in the Nicomachean Ethics, which scholars typically translate as “being at work” or “activity.” The work occurs when it transforms the energy from one system to another.
Energy is a central concept in all science, but it is abstract and difficult to perceive. We give it meaning through calculations and by assigning it measurements.
Types of Energy
Energy transformations occur among all kinds of energy, and there are many distinguishable classifications of energy. A few of the different forms of energy include:
Scientists break down these energy types into two categories: kinetic and potential energy.
Kinetic energy describes the energy in motion. Even the word itself refers to motion: it comes from kinetics, the Greek word that means moving. Mechanical energy falls under this category.
Potential energy is energy that gets stored. It includes chemical, elastic, gravitational, and more. The stored energy can do work. Nuclear energy is a type of potential or stored energy because it is energy stored in the nucleus of an atom.
Some types of energy fall under both categories of energy. Thermal energy particles include both kinetic and potential energy.
For energy transformation to occur, potential energy must always become kinetic energy.
Where Did Energy Come From?
If energy can’t be created or destroyed and remains fixed within a system, then how did it occur in the first place?
In theory, the energy available today has been around since the Big Bang. The Big Bang was the original energy transformation, at least within our universe.
Of course, there are still lots of questions about the Big Bang. Scientists only understand what happened in the moments after the event: no one knows what happened in the immediate moment that it occurred or what existed before.
One idea reflects on the notion of the “inflationary universe.” In an inflationary universe, space before the Big Bang included an unstable form of energy—one not yet known or understood by science. The idea suggests that at some instant, the moment the Big Bang happened, the energy transformed from the unrecognizable, unstable particles and became the kinetic and potential energy observed in our universe.
The implications of the inflationary universe model are unique. Effectively, if the Big Bang occurred as a result of the unstable primordial energy, then the expansion would bring even more of the unstable energy into existence. The theory suggests that all the energy that exists in the universe we study came from an amount of primordial energy where weighed about as much as a green pea.
Additionally, the model suggests that unstable energy was “lumpy” or not evenly distributed. As a result, it was able to spread out. If the primordial universe had seen a uniform spread of matter as it exists today, then the universe as we know it would not exist.
Is there evidence for this theory? Yes, astronomers observed the so-called “lumpy” primordial energy in the afterglow of the Big Bang, which captures images of the universe around 300,000 years after the exact instant of the Big Bang.
Can Energy Die?
The amount of energy in a system never changes: it is constant. It isn’t born, and it doesn’t die. But the matter it inhabits can and does.
Death is a part of life, but it’s something impossible to explore. We know that matter decomposes through biological processes, but what about the physical side of death?
When something or someone dies, their energy doesn’t die with them but gets redistributed.
The human body includes both energy and matter. The same is true of plants. When you are alive, there are roughly 20 watts of energy flowing through your body at any second. Most of the energy comes through food consumption (chemical energy), which we transform into motion (kinetic energy.
When you die, you no longer need the energy flowing through your body; you no longer gain it by eating or losing it through waste or heat. The atoms and the energy within them continue to exist in space.
It all goes back to the Big Bang. The atoms and energy created at that moment will always exist. So, the energy that courses through your body today won’t depart when your body ceases to function.
Your energy lives forever: it was here before you, and it will survive long after you. As physicist Aaron Freeman once put it: “According to the law of the conservation of energy, not a bit of you is gone; you’re just less orderly.”
Energy Transformation Experiments
To get a real feel for energy transformation, try out an experiment.
You don’t need a lab for these experiments. They are popular in elementary and middle school classrooms, but they help you understand what these definitions and equations mean in the real world.
Kinetic to Potential Energy
Our favorite classic physics experiment involves an apple. And why not? We can trace back some of the most quintessential concepts in physics to gravity and an apple.
To get started, you need an apple and a long piece of string. Tie one end of the line to the apple’s stem. Fix the other end to a point above your head so that the apple hangs at a point where it meets your forehead.
Take several steps back but remain within reach of the apple. Take the apple, and pull it towards you until it reaches your forehead. Then, let go.
The apple will swing away from you and then move back towards you, like a pendulum. However, the apple will not hit you when it moves back towards you. It looks like it will, but if you stay still, it won’t.
As you watch the apple, you’ll see energy transformation at work. The apple swings thanks to kinetic energy, but as it swings, some of the kinetic energy converts to potential energy as a result of the force of gravity. As the apple loses kinetic energy, it slows down as it swings before eventually coming to a complete standstill.
Heat Transfer Experiments
Thermal energy lives in the molecules of an object. When it heats up, the molecules move fast, but when it cools down there is less energy, and they move slowly. When they move faster, they take up more space.
Additionally, the Second Law of Thermodynamics provides that heat moves from hot objects to cooler objects through heat transfer to find an equilibrium.
Keep in mind that heat and temperature aren’t the same things. The term heat refers directly to the energy in the molecules, and the temperature is the measure of the average kinetic energy. They are closely related, but they aren’t the same.
Heat conduction experiments are a great way to see the process at work.
Place a pot of water on a hot burner. When the water gets close to boiling, place three spoons in the pot: a metal, rubber, and wooden spoon.
From here, the experiment happens quickly.
Place a pat of butter on the end of each spoon. You’ll see that the butter on the metal spoon melts away almost immediately because metal conducts heat incredibly well.
All this happens without movement from the spoons. Instead, the molecules of the spoons heat up, move, and transfer energy to the butter to melt it.
Energy Will Always Transform
Energy transformation is a fact of life. We use and re-use the same energy that the Big Bang created upon the birth of our universe.
Everything around you is energy and molecules, and everything undergoes energy transformation. Even your body converts chemical energy into kinetic energy to function and move.
The idea of energy is a profound one, and it shows just how relevant physics is to our daily lives. Has your understanding of the law of energy conservation changed the way you experience the world? Share your thoughts below.