I am having my students complete a general single replacement reaction with CuSo,(aq) and Fe(s) (in the form of steel wool.) The copper comes out of solution and seems to adhere to the steel wool. The solution itself turns light green showing that the Fe replaced the Cu in the solution. However, The solid Cu appears to bind to the steel wool threads rather than replace them. Does the Cu take on the shape of the steel wool threads or is there some coating going on?