# Do Physical Changes Require Energy?

By Antonia Čirjak on May 1 2020 in Science

• If we think about how an object moves, there is one crucial prerequisite that accompanies the notions of mass, speed, and energy. Remember, objects can travel with or against gravity, which ultimately affects the amounts of potential energy.
• In the formula E=mc2, the c2 is something known as a constant. The speed of light’s exact value is 299,792,458 meters per second. If you square that number and multiply it with the mass of an object, you get energy. Simple!
• You must look at the Law of Conservation of Energy as something that works in predictable, or better to say, controlled environments. Energy itself can be dissipated and lost in non-experimental scenarios.

Physical changes, where the matter of the universe goes from one state to another, requires energy. If we inspect this problem more in-depth, we can maybe start examining change and energy as notions that are closer than you might think at first.

## How Is Energy Conserved?

There are specific rules and laws about the energy that we will follow throughout this argument. One of them is a fundamental one, known as the Law of Conservation of Energy. The simplest explanation of this law says how energy remains as a constant when two objects are interacting with each other, changing the physical properties of each other. The conservation part of the law means that the energy that was there before the two objects interacted will be the same after the interaction (and reaction!) has been completed.

The other important distinction that will help us to explain the relationship between physical changes and energy is the way the transfer of energy happens between two objects. There are two different methods when it comes to this: exothermic and endothermic.

## Exothermic And Endothermic Processes

In exothermic processes (the process is the exchange of energy or the communication between objects), the heat is released out. For example, if you light a piece of paper on fire, you will feel and see the heat, and that energy is the heat released into your surroundings.

On the other side, an endothermic process happens when the heat gets absorbed from the outside into an object that is undergoing change. For example, for water to change its chemical state from liquid to gas, it needs to absorb the heat coming from some kind of source that has the potential to vaporize it.

To summarize, in any kind of physical or chemical change, the transfer of energy is always included. The more romantic way Law of Conservation of Energy can be put is that you can not destroy or create energy per se, you can only change its form.

## All That Has Mass Needs Something To Help It Move

Now, you can imagine how deep into the (sub)atomic world can we go to explain where this conversion of energy happens. In essence, it is quite simple: changing a chemical state is a process that occurs when the links between molecules start to break apart. That movement is, to explain it quite literally, the manifestation of energy. That is why the concept of stored (or latent) energy exists - everything that reacts has a specific storage capacity, which is based on, to mention just one obvious thing, the mass of an object.

This brings us, as it somehow always does, to Albert Einstein and probably the most famous formula in the world. E=mc2. From there, you can see how the notions of mass and energy live on two different sides of the equation, and their relationship explains the question we have at hand.

If the amount of energy depends on the mass (and, in this case, the squared speed of light), then all objects that have mass, and we will twist the formula in our direction: need the energy to move. That movement can be quite literal, like traveling from place A to B, or ‘’just’’ changing the physical and chemical properties. So, change is movement, and all movement needs energy.