It’s good stuff, and if you haven’t seen it you should watch it right now.
The narrative the Truther crowd has always pushed is that jet fuel burns at 1500 degrees and steel doesn’t melt until you get to a temperature well above 2300, and therefore hitting the Twin Towers with fully-fueled airliners shouldn’t have taken them down.
But you don’t have to melt steel to make it lose its structural integrity, as the video makes clear. Steel heated to a point where its integrity is compromised will give when pressure is applied to it, and even steel beams as thick as the ones holding up the World Trade Center buildings weren’t going to hold up after those buildings got hit by those planes, which by themselves would have created stress on the buildings not planned for in their design, and then massive amounts of jet fuel were set ablaze for a substantial period of time.
That somehow this is a difficult idea to get across to people is puzzling, but even 15 years later you have folks who insist that hitting those buildings with planes wasn’t a defining event on 9/11 but that there must have been more involved. It’s enough to induce a headache, and it’s nice to see someone who actually knows something about metal and heat expose this stupidity for what it is.