Unsourced gif appears to be from the series "Cosmos: A Spacetime Odyssey", episode 2, "Some of the Things That Molecules Do". Clip: https://www.youtube.com/watch?v=2I-PQxuPkjA

I believe it's a mock-up from NDT's Cosmos.

That’s CG, not a microscope.

Look at it go, weee!