upward

fluidization is just when you have enough upward air so that the force of the air pushing on each grain of sand is equal to the downward force of gravity or weight.

This makes it possible for a foundation to resist much more significant loads whether downward, upward or horizontal within a given footprint of a structure.

When you drink through a straw, you create a vacuum, allowing the pressure of the surrounding atmosphere to push your beverage upward.

It happens almost instantly, but you can see that the crack forms on the bottom of the beam, where tensile stress is highest, and propagates upward until the beam fails.