The Atom

In this segment of our “How small is it” video book, we cover the atom. We start with J.J. Thompson’s Plum Pudding model of the atom. We then introduce Alpha, Beta and Gamma radiation, and show how Ernst Rutherford used Alpha Particles in his scattering experiments to develop his version of the atom. We then cover Niels Bohr’s quantized atomic model along with input from Louis de Broglie who used the wave nature of electrons to show that they take the form of standing waves enveloping the nucleus instead of point particles orbiting the nucleus. We then introduce Schrodinger’s Equation, the Heisenberg Uncertainty Principle and the Pauli Exclusion Principle together with electron spin to fill out what we know about electrons around atoms.  We explain electron tunneling as an example of these concepts and introduce the Scanning Tunneling Microscope based on these concepts to see atoms by feeling them. In closing, we introduce the atomic nucleus and Chadwick’s discovery of the neutron, review how small the nucleus is and ask how it is that protons can hold together in the nucleus when there like charges should push them apart.