Every year as the season starts I read where folks talk about how such-and-such a board is stronger/stiffer/better because of the use of a specific resin or fabric.
I like to do this test as an example of demonstration that resin and fiber, while important, have less impact than the construction and thickness of the board in determining final stiffness.
This is a picture of some crappy 1 pound Lowes insulation that is 1" thick and about 1.5" wide. It's suspended between two containers and I can get about 40 oz of weight on it before it get dangerously close to breaking.