Small Angles and Small Particles

The structure of matter is an ancient mystery which continues to provide fruitful ground for study. Strangely enough, we possess more reliable information on the structure of atoms and small molecules than on the structure of colloidal particles and macromolecules which are very many times larger. Partly this is so because such particles are of greater complexity and occur in greater diversity than their atomic constituents, but it is also owing to the lack of adequate techniques for examining and measuring these particles. Among the tools for such study is the scattering of radiation by a substance.