Nuclear Physics Explained

See how the strong and electromagnetic forces shape the nuclei of all atoms. Focus on the curve of binding energy, which explains why heavy nuclei are prone to fission, releasing energy in the process, while light nuclei release energy by fusing. Visit some classroom lab equipment to explore the principles that govern particle accelerators, which are used to probe the structure of nuclear matter.

Now turn to unstable nuclei and the process of radioactive decay. Trace three types of decay - alpha, beta, and gamma - studying the particles involved, their charge (or lack thereof) and energy ranges. Measure radioactivity with a Geiger counter, and consider what it would take to shield against each type of radiation.

Survey the sources of radiation in the world around us, bombarding us from the sky (cosmic rays), found in the ground (uranium and other naturally occurring radioactive elements), zapping us in medical procedures, and found in consumer goods. Look at some long-discontinued radiating products such as shoe fluoroscopy and Radithor, an ill-advised radium-laced health tonic.

Radiation terrifies many of us, but how scared should we be? Probe the difference between ionizing and non-ionizing radiation, focusing on what high-energy emissions do to DNA. Consider a host of radiation sources - from the innocuous, such as cell phones and power lines, to nuclear explosions and dirty bombs. Finally, learn what to do if you are ever exposed to nuclear fallout.

Now open the hood to see how the nucleus works. Start simple with a hydrogen atom, which has a nucleus of one proton orbited by a single electron. Build from there, adding neutrons and more protons, forging elements and their isotopes and seeing how the nucleus behaves much like a liquid drop. Then use the Fermi gas model to refine your understanding of nuclear structure.

High school chemistry introduces students to the atomic shell model, which describes the distribution of electrons around the nucleus. In this lecture, learn the analogous nuclear shell model and the magic numbers that constitute full shells of protons and neutrons within the nucleus. Also, discover how an entire nucleus can ring like a bell or spin like a top.

Take a behind-the-scenes tour of the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, where Professor Weinstein and his colleagues use high-energy electron beams to probe the structure of the nucleus. Dr. Weinstein also explains other types of particle accelerators and their purposes, including the Large Hadron Collider in Europe.

Subatomic particles are inconceivably small and move unbelievably fast. So how are they detected? To learn the ropes, go into an instrument facility where detectors are built. Begin with the simple circuitry of a Geiger counter, invented in the 1920s, and graduate to state-of-the-art tools that are millions of times more sensitive, including scintillators and wire chambers.

Continue your tour of Jefferson Lab by learning how scientists design an experiment, get it approved, run it, and then analyze the results. Discover why interpreting the outcome of nuclear collisions is like reconstructing car crashes. One tool relies on the shock wave produced by particles moving faster than light, which is possible in mediums other than a vacuum.