All great educators and parents inspire us to reach our potential – to discover parts of us yet to be realized.
Potential energy in science is not much different. This lesson explores the concept of energy that has the potential to do work.
Definition of Potential Energy
Why would a stretched rubber band aimed at your face, a rock being held over your head, and a live electrical wire on your street make you nervous? All of the objects are in positions that can potentially hurt you. In other words, they have energy ready to be released, and when it is, these objects will do work.Now, imagine a rubber band just sitting in the palm of your hand, a rock on the ground and a wire without any power. These same objects no longer pose a threat.
Why? Because they are in different positions and no longer have that energy that has the potential to be released.In science, energy is often described as the ability to do work. So, potential energy is energy that can do work at some point in the future. The first scenario described items that all had potential energy. While this potential energy is waiting to do this future work, it must be stored somehow.
Due to this, potential energy is also often referred to as stored energy.
The next question that comes to mind might be, ‘Where is energy stored?’ But considering that energy is an elusive, unseen thing, the more appropriate question may be, ‘How is energy stored?’ The general answer is expressed in terms of position. How an object is positioned or arranged in relation to other things can result in the storage of potential energy.
Let’s take a look at another example – this huge boulder:
If those smaller rocks were not there, what would gravity do to the boulder? Of course, the boulder would crash down so hard you definitely would not want to be standing underneath. Just moving a short distance, the rock does a large amount of work once its potential energy is released.If this rock was on a hill and started to move, gravity would pull it all the way down to the bottom as long as nothing blocked its path. Clearly, a rock that size storming down a hill would release a ton of energy and do a lot of work.
Imagine all of the things it could crush. This energy was created because it was located up on top of the hill. Once the rock is at the bottom of the hill sitting on flat ground, it no longer has any potential energy.
The rock does not have the option to fall down anymore; it is not elevated against gravity.
Types of Potential Energy
So, what are the different kinds of potential energy? Any object located at a position above the ground, where it has the possibility of coming down to the surface, has potential energy. In particular, this is called gravitational potential energy because gravity is the reason elevated objects have potential energy. The higher an object is off the ground the greater the downward pull of gravity is, and the more potential energy it has.
This is why people have no problem jumping off the bottom step but prefer not to jump down a whole flight of stairs. Just that far off the ground, we simply have too much potential energy.There are actually several other types of potential energy. Each type involves the positioning of objects in some way that they are able to store energy.
Recall the stretched out rubber band? This is called elastic potential energy, or the potential energy stored in an object that is stretched.Electrically and magnetically charged objects can generate potential energy based on their known interaction with other charged objects. For example, if two atoms both have negative charges, there is a potential energy between them simply because they both have the same charge. That is because they will predictably release this energy in a repellent motion when brought close together. Remember, any motion an object makes is a use of energy. In this case the potential energy of the charge interaction is used when the two objects repel with movement.
Similarly, imagine two positively charged objects. They both have potential energy in relation to each other. There is a release of this potential energy as they come closer together with motion that would not have occurred if they were not oppositely charged. Along the same vein, if one object is charged and the other is not, there is no potential energy, because when brought together, there is no extra movement that occurs.
- Energy: in science, the ability to do work
- Potential energy: energy in reserve for the future
- Gravitational potential energy: any elevated object has energy potential due to gravity
- Elastic potential energy: potential energy stored in an object that is stretched
Upon absorbing these facts about potential energy, it should be easier for you to:
- Demonstrate understanding of the definition of potential energy
- Discuss the storage of potential energy
- List the types of potential energy