are first detected. Another method includes the probability distribution model, analogous to the methods used to study supercooled liquids, where the probability of finding at least one nucleus at a given time is derived. Properties The properties of a material in nanoparticle form are unusually different from those of the bulk one even when divided into micrometer-size particles. Many of them arise from spatial confinement of sub-atomic particles (i.e. electrons, protons, photons) and electric fields around these particles. The large surface to volume ratio is also significant factor at this scale. Controlling properties The properties of a nanoparticle are heavily influenced by the initial nucleation stages of the synthesis process. Nucleation, for example, is vital to the size of the nanoparticle. A critical radius must be met in initial stages of solid formation, or the particles will redissolve into the liquid phase. The final shape of a nanoparticle is also controlled by nucleation. Possible final morphologies created by nucleation can include spherical, cubic, needle-like, worm-like, and more particles. Nucleation can be controlled predominately by time and temperature as well as the supersaturation of the liquid phase and the environment of the synthesis overall. The properties of a material in nanoparticle form are unusually different from those of the bulk one even when divided into micrometer-size particles. Many of them arise from spatial confinement of sub-atomic particles (i.e. electrons, protons, photons) and electric fields around these particles. The large surface to volume ratio is also significant factor at this scale. Large surface-area-to-volume ratio A bulk materials (>100 nm in size) are expected to have constant physical properties (such as thermal and electrical conductivity, stiffness, density, and viscosity) regardless of its size, for nanoparticle, however, this is different: the volume of the surface layer (few atomic diameters-wide) becomes a significant fraction of the particle's volume; whereas that fraction is insignificant for particles with diameter of one micrometer or more. In other words, the surface area/volume ratio impacts certain properties of the nanoparticles more prominently than in bulk particles. Interfacial layer For nanoparticles dispersed in a medium of different composition, the interfacial layer — formed by ions and molecules from the medium that are within a few atomic diameters of the surface of each particle — can mask or change its chemical and physical properties. Indeed, that layer can be considered an integral part of each nanoparticle. Solvent affinity Suspensions of nanoparticles are