Static

We started by observing a pipe that attracts a can and bends water!

What do these two examples have in common? The pipe, the can and the water all have electrons and protons! Rubbing the pipe with the cloth charges the pipe with electrons. They attract the protons in the can and in the water. The can rolls off the table towards the pipe and the water bends towards the pipe too! Let’s see the math in more detail:

The can and the pipe are balanced to start: 1 electron and 1 proton each (attracting each other).
The proton has force 2 repelling from the pipe and force 2 attracting to the pipe. Same for the electron.
The can does not movel
The cloth charges the pipe with 1 extra electron turning it into a anion (atoms that are negatively charged).
The proton has force 2 repelling from the pipe and force 4 attracting to the pipe. The opposite arises for the electron.
But the can still does not move!
However, the electron has a force of 4 repelling from the pipe and a force of 2 attracting to the pipe! The electron inside the can moves creating a anion far from the pipe and a cation close to the pipe!
As a result, the forces on the electron reduce and the forces on the proton increase because the cation is much closer to negatively charged pipe.
There is more force acting on the can towards the pipe and the can will move with it!
The end!