Now, that's a damn fucking lie, but hey, it's far easier just to claim something is "fact" and not demonstrate a comprehensive understanding of the equations and models behind such "facts."
To those with not much of a technical background in chemistry, physics, and the engineering fields, here's a little secret: we cannot prove anything as absolute fact! Every scientific law and equation is a mere approximation of a mechanism of the universe- which all have varying degrees of error under varying conditions and circumstances. A good scientist, researcher, or engineer should not blindly accept any scientific claim as absolute fact, but should be to assign a probability to such claims and show its potential error is within an acceptable range.