Demonstration F1-11: Hydraulic Press is a popular and dramatic way of illustrating Pascal’s Law. See it in action in this new video starring engineering student Sarah Hall:

Pascal’s Law states that, given an incompressible fluid, any change in pressure at one point in the fluid is transmitted throughout that fluid. In a closed container, like this hydraulic cylinder, that pressure exerts a force perpendicular to the walls of the container. The force is dependent on the pressure and on the area. Here, that force is then transmitted up into a wooden board, breaking it.

 You can see this illustrated in this EduMedia animation: https://www.edumedia-sciences.com/en/media/442-hydraulic-lift

Experiment with it yourself and see how the force vectors change with area in this simulation by Seng Kwang: https://physicslens.com/hydraulic-press-simulation/