scattering, particle

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scattering, particle Deflection of electromagnetic radiation by particles. Where the particles are very much larger than the wavelength, scattering consists of a mixture of reflection and diffraction, and the amount of scattering depends very little on wavelength. Where the particles are very much smaller than the wavelength, the amount of scattering is inversely proportional to the fourth power of the wavelength. Thus, small particles scatter blue light ten times as much as red light. Elementary particles can be scattered by atomic nuclei or other particles. It is the means by which the structure of atoms was discovered. Hans Geiger and Ernest Marsden, students of Ernest Rutherford, ‘fired’ alpha particles through thin metal films and noted their scattering. From the results, Rutherford deduced the existence of the atomic nucleus. Most knowledge of elementary particles and the discovery of new ones has been obtained by scattering experiments carried out in particle accelerators.