The FPM can also be used to simulate the spatial and temporal evolution of the chemical composition of the particles. To do this, modes can be composed of multiple, immiscible phases, and each phase can be composed of multiple species. For each additional species, the FPM requires the solution of an additional scalar.
Below is a schematic of a multiphase particle that can be represented with the FPM. One phase is used to represent the solid core, and a second phase is used to represent the liquid mantle. Each phase can include multiple components.