Why does wet sand turn into almost a liquid when it is shaken?

Question

So normally, wet sand usually is pretty solid, you can crumble it and other things, but when you shake it, it almost loses all its solid properties and flows. Why does this happen?

In: Geology

Answer 1

Because when you shake it, the friction/movement is enough to jostle the structure of the block of sand. As many pieces break away from each other, the 1000’s of little breaks loosen the structure enough for them to break away from the faux solid you made.

Think of when you sieve flour through a strainer, pretty much the same thing.