Welcome to the Science Asylum.
I am Nick Lucid.
I’ve noticed lately that I’ve had a lot of energy.
[Exercise Noises]
It’s just bursting to get out of me and that got me thinking:
What is energy? I mean, what is it really?!
The problem here stems from our limited ability to define things in our language.
So to deal with this problem, I started with the Online Etymology Dictionary to find the origin of the word itself,
which turned out to be Ancient Greek for “at work” suggesting only what I already knew:
Energy gives us the ability to do stuff.
In fact, all the definitions in all the dictionaries and science books seem to have that same problem.
They tell us what energy does, not what it is.
What is it?!
We really only have two ways of understanding things
First, we could compare and contrast with something we already understand.
or, second, we could divide it into parts and categorize them.
Unfortunately, energy is unlike anything we’ve ever seen before
and it appears to have no parts whatsoever,
which leaves us in a bit of a pickle.
Hmm.
Wait, it does look different when it’s in different places.
What? You’ve never seen energy before?
That’s because you’re using your eyes.
You’ve got to use your mind’s eye.
Go find your imagination and dust it off.
Got it? Ok, cool.
If we can find out all the places it can be,
then maybe then we’ll have a better idea of what it is.
Can we make a list?
Definitely! I love lists.
We've seen stuff nearby other stuff.
We'll call that potential energy.
We've seen stuff moving.
We can call that kinetic energy.
We've felt stuff be really warm.
We can call that thermal energy.
We've seen stuff shine.
We can call that light energy, I guess.
And stuff explodes too, which has to do with chemical and nuclear energy.
Oh! And, uh, life is a thing.
I mean, our bodies are just chemical energy machines, right?
You know what might be even better for this than a list?
A concept tree!
Ok, let’s see, move this over here, move that over there, and voila!
That’s a lot of different energies.
No way is the universe really that complicated
and what the heck is this stuff, anyway?!
Internal energy is the energy inside stuff,
so that must have something to do with the molecules making up the stuff.
We need to imagine a little smaller.
Molecules move, spin, and wiggle, so that’s just kinetic energy.
They do have a tendency to stay together,
but bounce off each other when they get too close. That’s potential energy.
Chemical energy is what holds the atoms together in a molecule.
Again, that’s potential energy.
Nuclear energy is holding the atomic nucleus together, so that’s just potential energy too.
Ok, this is looking a lot better.
Everything is just potential energy, kinetic energy, or mass.
So what’s mass?
That’s not a simple question to answer fully,
but the short version is that it depends on how you're looking at the stuff in question.
If you’re so close that you can see the quarks inside the protons,
then it doesn’t look like there’s a whole lot of mass there.
But, if we zoom out, it just looks like a single proton.
All that potential energy holding the quarks together looks like mass because we really can’t see it anymore.
The point is that almost all the energy we call “mass"
is just the potential energy in the nuclei of the atoms.
You're mostly just empty space.
So, in the end, energy is really just potential energy and kinetic energy,
some of it just happens to be in the tiny nooks and crannies inside things.
This hasn’t really answer our question yet.
No, I guess it hasn’t. Huh.
On top of that, kinetic energy is kind of weird.
I mean, the driver of a car has kinetic energy, right?
Well, what if you’re a passenger in that same car?
As far as you’re concerned the driver is sitting still.
No no, the Earth is stationary and we’re both moving.
The Earth is stationary?
What about it rotating once a day?
Or going around the Sun once a year?
Or zipping around the center of the galaxy with the Sun?
So yeah, this leaves us with an unfortunate truth.
We don’t really know what energy is.
Every hypothesis we've ever had that has pretended it’s some kind of substance has epically failed.
It seems to only be this weird abstract property of the universe.
Energy is just a number and the total amount never changes.
So, what do you do when you have a lot of energy?
Wink wink, nudge nudge.
Please share in the comments.
And until next time, remember, it’s ok to be a little crazy.