Demonstrations based on physical objects aren't mathematically precise. Who's to say that the wood doesn't flex, or that the fluid doesn't compress? You can see

Demonstrations based on physical objects aren't mathematically precise. Who's to say that the wood doesn't flex, or that the fluid doesn't compress? You can see that the areas are equal to within measurement tolerance, but not that they're exactly equal. Here's a classic 'physical' pictorial proof that 31.5 = 32.5: https://jeremykun.files.wordpress.com/2011/07/31equals32.png https://jeremykun.files.wordpress.com/2011/07/31equals32.png