Measuring the Very Small

To begin our study of matter we discuss experiments in the late 19th and early 20th centuries which led to proof of the existence of atoms and their constituents. We then introduce a fundamental idea about scattering of waves using the diffraction of light by small particles as a prototype. The famous Geiger-Marsden experiment which lead to the idea of the atomic nucleus is discussed. Finally, we examine some of the crucial experiments done with modern particle accelerators and the physical principles behind them.^19.1