[macman104]

So you'll notice that when looking at the picture, the pi bonds are above and below the plane, if you were to try to rotate this molecule, what would happen to the overlap of the p-orbitals that allows for the pi bond to exist?  Would there still be an overlap as you rotate the molecule?

[student8607]

If you rotated one of the atoms (like a marble) then it would break the sigmoid and pi bonds?

I'm not really understanding. I guess the pi bond would be broken? So thats why so much energy is needed?

[macman104]

Right, the sigma bond won't break because it is along the axis of the atoms, however the pi bond is above and below the plane of the atoms, and if you rotate, the alignment of the p-orbitals will be broken.

[student8607]

Gotcha. Thanks.