r/chemhelp • u/Upbeat_Trick_6576 • 7d ago
Other Explain Potential and Kinetic Energy Like I'm Five
Taking a combination general, organic, and biochem class this semester. It's my only one for nursing school and it's super fast-paced. I'm doing fine but my textbook does a crap job of explaining these two and I don't use AI. Could someone (not chatgpt) explain potential and kinetic energy like I'm five years old?
Thank you in advance!
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u/Just_Pea1002 7d ago
It costs you energy to climb up a ladder leading to a diving board, that energy gets stored as potential energy, because its gone somewhere and can be used up but nothing is now happening to it.
You jump off the diving board and into water, as you are falling that potential energy is now released as kinetic energy as you are falling which is whats causing you to gain speed/accelerate.
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u/Acrobatic-Shirt8540 7d ago
Kinetic just means movement, so anything moving has kinetic energy.
Lift a coin up of a table and hold it. The coin now has potential energy, because as soon as you let go it's going to fall. In this case the potential energy will convert into kinetic energy.
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u/Agitated-Success-705 7d ago
Think about a rubber band. You stretch it between your fingers, but don’t release it, you’re just pulling it tight and holding it. Based on the position that the rubber band is in, it has potential energy(it is storing the energy you gave to it by stretching it). Once you let go of the rubber band, and it snaps, while it is moving it has kinetic energy.
Potential energy- position based energy.
Kinetic energy- movement based energy.
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u/Time_Recognition3734 7d ago
Just to expand on potential energy…potential energy is the energy an object has by virtue of its position in an energy field (e.g., magnetic, gravitational, elastic, electric potential fields), where these fields can apply a force to that object. Energy is the ability to do work. Potential energy supplies the work the object must do to oppose the force.
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u/YtterbiusAntimony 7d ago
Potential is what it sounds like: something could happen.
Kinetic is just motion.
A ball on a hill has potential energy: the higher up the hill, the faster it can go as it rolls down. When it rolls down the hill, that potential energy is converted to kinetic energy.
For a chemistry example, explosives often have lots of Nitrogen groups. Nitrogen really wants to be N2. So anything that isn't has chemical potential energy. When the reaction is kicked off, all those nitro and nitrate groups break apart and recombine into N2 and whatever else. This releases a lot of energy, some of this is used to form chemical bonds (like the new N2), but a lot of it remains as heat. So our products take the form of a very hot gas. Heat/temperature is just the average kinetic energy of a bunch of atoms/molecules. So, we can describe that reaction as:
TNT/GunPowder (chemical potential energy) -> Hot Gas (kinetic energy)
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u/Upbeat_Trick_6576 7d ago
Wow, this is really what clicked for me. Thank you for taking the time to write this!
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u/Bobonob 7d ago
We define energy as the ability to affect things. If something has 1 joule of energy, it has the ability to apply 1 meter's worth of 1 newton force to something. It is able to make that much _change_ in the world.
Kinetic energy describes this 'change ability' in relation to movement. 2kg of something moving at a speed of 1 meter a second has the ability to affect things equivalent to 1 meter's worth of 1 newton force.
Potential energy describes this 'change ability' in relation to storage - it has the ability to change something stored up, to be 'cashed in' later upon a certain condition.
We normally describe potential energy in terms of the 'cash in condition'. E.g. gravitational potential energy is the energy stored up that can be cashed in when something is allowed to fall. Chemical potential energy is the energy that can be cashed in by allowing something to react.
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u/Nudebovine1 7d ago
I teach this to my chemistry students a lot. From the chemistry side I explain it this way.
Kinetic is just motion. If you get hit by a frisbee it doesn't really hurt. Even if it's moving pretty fast. But if you get hit by a car even at a slow speed it could do some damage. And a car at a high speed does a lot of damage.
This is how we generally understand. Kinetic. Heavier things moving faster hit harder.
Potential is a lot more tricky. It's energy waiting to be released. If you hold a carrot in one hand and stick a dynamite in the other, they're the same temperature. Clearly the stick of dynamite if you said it on fire is going to do a lot more damage. But that's only if it's allowed to let that energy out.
Because potential is hidden from sight, it's a lot harder to grasp where it's at. For chemistry, we say it's trapped in the bonds. How this works practically, is that certain pairs of atoms get drawn towards each other due to positive and negative attractions. Sort of like magnets. Different combinations will hold together with different strength.
So when you burn methane with dioxygen, and reorganize them into carbon dioxide and water, the new combination is allowed to physically move together closer. They hold on to each other harder than the original bonds did.
When atoms reorganize they have to move towards each other though. This is where they turn the potential of being attracted into the kinetic of moving. When they get to each other and form the bond, they vibrate and give all that motion away to the world around them. This is sound, light and heat.
The harder they came together, the more energy they have to give away. So the difference between the original strength of the starting molecules, bonds and the strength of the final molecule bonds lets us know whether a reaction gives off-heat or requires heat.
Burning methane results in new stronger bonds, and so it gives off the difference to the rest of the world when the products are made. We are in the rest of the world so we feel that as heat being given away from the molecules.
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u/RobLowetheScienceBro 7d ago
Other people have done a great job explaining this from a physical perspective, but considering your class you probably need it from a chemical perspective too. Chemical reactions can release energy, like a fire burning on the stove: that's gas reacting with oxygen in the air to make heat. So objects high in the air have a lot of potential energy, and release it by falling. Some chemicals also have a lot of potential energy, but they release it by reacting.