Hey everyone, I was thinking about the physical solid texture ash and how it form. The wood ash, fly ash, volcanic ash, and soot--types of Ash all look visually different and are cause by different thing; however, they all appear to have a similar texture that we associate with Ash and sometimes even dust. This made me wonder, what exactly in the process of burning causes ash to look the way it does? Is there a common thermodynamic property related to ash? Is are there conditions required for ash to form in exothermic reaction? What exactly is the physics behind ash and ash formation?