 Okay, so let's attempt to use our butane structure here and draw an energy diagram of all of the structures of butane, okay? So we'll start at the very high energy, what did we call this, the, you guys remember, sin-periplanar, right? Okay, we'll start at the very high energy sin-periplanar. We draw a circle, then a dot in the middle, and it's the sin-periplanar, it's a, what is it, eclipsed or stacked? Eclipsed. So draw like that, and then what do we say, the two big groups are eclipsing each other, okay? So again, I hope we have enough room. If we don't, then we'll just kill this video early. But like we're saying, high energy, okay? So this is a very high energy combination. Then we're going to turn it 60 degrees. So from this conformation here, we're going to turn it to here, okay? That's, this is what, eclipsed and sin-periplanar. So the next one is going to be what, if we turn it 60 degrees? Stagger, right? And gauche, yeah, very good, that's good. So is it going to be lower in energy, what do you expect, or higher in energy than the eclipsed sin-periplanar? Lower. Lower, right? Okay, so, and we want to keep one of those carbons the same. Let's keep that back one the same like I did earlier, okay? So methyl group, hydrogen, hydrogen. And then the methyl group was there, there, and there. So this is a staggered form, and we called it what else? Gouche, yeah. Why do we call it gauche? Because the two big groups are 60 degrees away from each other. So that's that steric interaction there, that's a Gouche interaction. Is everybody okay with talking like that? Yes. Why 60 degrees? Why 60 degrees? Because that's just in between there and there. And then we'll do it there, there, there, there, and then all the way around. So we can have, so what we'll do is 60, 120, 180, and then get all the way back to 360. I mean, it can go to 53 degrees or 42 or whatever, you know, but once we get here, then we call it a new name. Yeah, so yeah, there's just no, no, I don't know, synchronized name for these other conformers, if you will, in between 60. So we'll say this is zero, this is 60 if you want to do that, okay? Okay, so let's move it again. So if we move it here to here, right, that's going to be a what conformation? Eclipse, yeah, or 120, so we'll move it, 120, and it looks like we might only get to 180. But it's going to be an eclipsed one, okay? Eclipsed are higher in energy than the staggered, but it's going to be lower in energy than this sin-peri-planet, okay? So it's going to be in between the energies here, is everybody okay with that? So let's just draw that. Keep the one the same that you've been keeping the same, and now we've got the methyl group here, hydrogen there, and the other hydrogen. Is everybody okay with that? Okay, so this we just called eclipsed. Yeah, so let's look at this guy here, okay? So we started here, right, and then we moved to here, there, and now we did to there, okay? So you see these are eclipsed, this one and this one are eclipsed here. You see that? It's still higher than the, the energy is still higher than the staggered one? Yes, yeah, so it goes up and down, okay? Like that, do you see? Okay, if you need to come up after the thing and look at it, okay? So then what happens? Then we're going to turn it what? 60 more degrees, and what's that going to be called? The anti-peri-planet, right? That's going to be high or low in energy? Very low, very low, right? So let's draw that one. So down to 180 degrees now, so for the low degrees. So very low in energy now. So this one here is called a staggered one, and we called it also anti-peri-planet. And that, that second eclipse, there's no ghost, should nothing do it? Well, remember the ghost interaction is when two big groups are 60 degrees apart from each other, so you can't have a ghost shown in the eclipse. So is everybody okay to where we've gone so far? Okay, wonderful. Now, if we turned it another 60 degrees, what would we get to? Something that looked like something else up here? A staggered ghost. So we would get back, so if we turned it, well first we got to turn it just 60, right? So what would we get to? This guy again, right? Except the methyl group would be on this side here. Okay, so let's do that. So that would be what? 240. So this we call an eclipse. It's supposed to be the same high as this one, but it's hard to do that on a uniform. Then we'll turn it again, right? To what? 230. And what will we get here? A ghost one. Yeah, very good. So that ghost one, so we're going to have this one, right? So this is called staggered ghost. Why? Because the two big groups are 60 degrees away from each other. 60 degrees away from the carbon groups? Big groups, okay? Big groups. So right now, in butane, all we've got is methyl groups. But if you had an iodine instead of a methyl group, that would be bigger than a hydrogen. Okay, it's just one of the big groups are 60 degrees from each other. And then the last one, 360, what would we get back to? An eclipse, but more importantly, the sin-periplanar. So it's going to be way up at the top. I'm going to put it way up. The exact same one as over there, as I drew it so high. And this one's going to be, of course, eclipsed. You can kind of see a graph going like this. You see that? You guys see that? So that's the whole of the rotation. So this is the rotational energy graph for butane. So be sure to be able to reproduce something like this. For ethane, it's much easier. It's just going to go staggered eclipse, staggered eclipse, staggered eclipse, staggered eclipse. If you want to, you can come to office hours and we can do that one, too. But this one's a little more intense, so I thought I'd do this one. Any questions before we kill this video? Wonderful.