They react to produce sodium solid. So really, as our reaction progresses, our concentration of sodium ions increases in beaker one and decreases in beaker two. So, in a way, we can think of our sodium ions traveling from this speaker beaker two to beaker one, from the cathode to the anode. And that is exactly why we consider this speaker one to be the inside and this speaker two to be the outside, right? Because initially on the inside, we have less sodium ions than on the outside. Here, we have more.