The pressure difference is trivial. The reason it has to be thicker is because the top is flatter than the sides (convex) and bottom (concave). If the top was domed up it could be thinner. Have you ever seen an overheated or frozen can? The top is usually bulging while the rest is still intact.
Re:What Coke Contains (2013)
by electromagnetic on Sunday September 21, 2014 @02:36PM
(#8347885)
Actually most frozen cans have the bottom inverted, but I've only noticed this happen since about 2010. It used to be that a fully frozen can always used to blow.
Top also needs to be stronger to handle the stress of the flip-top, which -- fun fact! -- starts off as a second-class lever and ends up as a first-class lever.
Nope, the pressure from the carbon dioxide pushes equally against all sides of the can. If anything the pressure at the top is slightly lower than at the bottom, at least if the can is standing, because of the weight of the coke pushing against the bottom.