<P> A homogeneous mixture is a solid, liquid or gaseous mixture that has the same proportions of its components throughout a given sample (or multiple samples of different proportion). Homogeneous mixtures can have a variable composition . Conversely, a heterogeneous mixture is not uniform in composition, but proportions of its components vary throughout the sample . "Homogeneous" and "heterogeneous" are not absolute terms, but depend on context and size of the sample . In chemistry, a homogeneous suspension of material means that when dividing the volume in half, the same amount of material is suspended in both halves of the substance . However, it might be possible to see the particles under the microscope . An example of a homogeneous mixture is air . </P> <P> In physical chemistry and materials science that refers to substances and mixtures which are in a single phase . This is in contrast to a substance that is heterogeneous . </P>

Matter that is not the same throughout is called