CHEMISTRY COMMUNITY

How do we know if the galvanic cell has a porous disk or a salt bridge? What's the difference between the two?

With how many lines would a porous disk be represented in a cell diagram?

| = interfaces between phases in contact with each other.
||= salt bridge.
? ?= porous disk.

I think I remember Dr. Lavelle saying that the porous disk is one line when he was making announcements about our midterm, however I'm not too sure.

A salt bridge is an inverted u-shaped tube that contains an electrolyte and allows the two half cells to be connected so ions can flow freely and the charge between the half cells remains balanced. A porous disk allows cation/anion flow as well but takes the form of a disk in between the two solutions. With a porous disk the half cells aren't in two completely separate containers, unlike when the half cells are connected by a salt bridge. Salt bridges are denoted by two vertical lines whereas porous disks are denoted by one vertical line (although usually two vertical lines or a single vertical dotted line are accepted as well). Basically if the solutions are in two separate containers there is a salt bridge but if the solutions are in the same container they are separated by a porous disk.

What is the porous disk composed of? Does it act differently than the salt bridge in any way?