You can think of a higher energy state for some objects as sort of the cocked state.
What am I talking about?
Let me show you an example. Here's a little rubber band.
It's a hair rubber band that I use to put my hair in a ponytail.
Now, by itself, the little rubber band doesn't have much energy.
I could drop it, okay?
But, if I dropped it it would just go down.
But I can cause the rubber band to have more energy by stretching it.
If I stretch it and I point it at you, Right?
Now it's got more energy and I could shoot it at you, right?
So by
stretching the rubber band, by putting it into the cocked state, if you
will, I have put energy into the system that is the rubber band.
Now I had to do work to do that, okay?
But if I let go, right, the initial state
here is high energy because it's stretched, it's cocked, and
if I let go, the final state would be it
would fly through the air and it would land somewhere.
The final state would be lower energy, right?
And so by letting go of the rubber band here, the Delta E for
that process, the change in the energy of that process would be negative again.
Let me show you one more example, and I wish I was Julia
Child and I had some men down there to hand me my props.
But I have to get it myself. So, I'll disappear for a minute.
Here I am! Okay, here I have a bow!
This is a little toy bow that we bought as a prop
for a costume party, and I have a real arrow on it.
A target
arrow, see the tip of it there?
kind of long, the arrow is for a larger compound bow, but
I brought this little toy one because it's easy to see.
Now with the arrow sitting on the string of the bow, you can see the
bow if I turn it sideways there, OK,
there's not any energy in the arrow, right?
It's not going anywhere. It's just sitting there.