While humble movie director James Cameron spends his free time exploring the Mariana Trench or funding asteroid mining operations, actual scientists are still obsessing over his 1997 blockbuster "Titanic."
Some loose message board ponderings led to a small faction of internet eggheads on Reddit (via Gawker) to crack the code of whether or not Jack and Rose could have both stayed afloat on that famous piece of wood, and it turns out Kate Winslet wasn't being a selfish plank hog after all: they would have sunk.
We're a little rusty on our physics, but their math basically says that in a battle between the Force of Buoyancy (the planks ability to stay afloat) vs. Force of Gravity (how frickin' fat Kate and Leo were) gravity would have won.
While this doesn't mean the two actors should have had a few less servings of that First Class caviar (they were 130lbs/58.9kg and 160lbs/72.6kg, respectively), it simply means the door was only 6cm thick, and since it weighed in at 64.9kg then that plus the actors' weight times the acceleration of gravity at sea level (9.81) comes out to 1926.684 Newtons, far greater than the 882.9N which is the maximum force that can be produced through buoyancy.
So there ya go. Bar bet settled.
"You're welcome! We're science: we're all about coulda, not shoulda." – Patton Oswalt