Evidence for Modern Physics: How We Know What We Know

Peer inside atoms to find mostly empty space, along with electrons and a compact nucleus, composed of protons and neutrons. These particles were all discovered indirectly through painstaking but straightforward experiments. Learn how physicists used more complex tools to uncover hundreds of even smaller objects. It took the quark theory to bring simplicity and unity to this seeming chaos.

Probe one of the most baffling mysteries of physics: the wave-particle duality of light. Trace the debate over the nature of light to its apparent solution in 1801, when Thomas Young demonstrated that light is a wave. A century later, Einstein proved that light also behaves as a particle. Astonishingly, further work showed that electrons and other matter also have this Janus-faced identity.

Dr. Lincoln boldly confronts the paradox of quantum entanglement, which governs the behavior of particles that share the same quantum state. Discover that the rules of quantum mechanics defy every attempt to explain what seems inexplicable -- implying, for example, that a cat could be simultaneously dead and alive in Erwin Schrödinger's famous thought experiment. Explore other spooky examples.

Learn how Dr. Lincoln routinely conducts experiments that show the bizarre effects of Einstein's special theory of relativity, which come into play at speeds approaching that of light. Like quantum theory, relativity strains credulity, but clocks really do slow down and length contracts at relativistic speeds; we just don't notice these effects in our relatively slow-moving lives.

How can the speed of light be the same for everyone, regardless of their state of motion? First, investigate how the speed of light is determined. Next, consider the hypothesized medium for light propagation -- the aether -- which was dealt a fatal blow by the Michelson-Morley experiment in the 1880s. Finally, examine laboratory proof that the speed of light is constant for all observers.

Survey the fundamental particles and forces of the Standard Model, which is the prevailing theory of particle physics. Then focus on nonfundamental particles and their discovery tools, such as the cloud chamber. Easily built at home, the cloud chamber reveals the products of radioactive decay, including antimatter -- which sounds like science fiction but is an authentic feature of reality.

Learn the secret for measuring the masses and lifetimes of subatomic particles that exist for roughly a trillionth of a trillionth of a second. Using the Higgs boson and top quark as examples, Dr. Lincoln draws on a simplified version of Einstein's mass-energy equation and Werner Heisenberg's uncertainty principle to infer detailed information about truly ephemeral entities.

Hear the story of the neutrino, the ghostly particle that passes through you at the rate of one quadrillion per second, with no ill effects. Neutrinos are created copiously in nuclear reactions and are fiendishly difficult to detect. Pinning them down took great experimental ingenuity, especially since neutrinos turn out to be quick-change artists, often transforming their identities in flight.

As a member of the research team, Dr. Lincoln recounts the discovery of the Higgs boson, one of the major science stories of the past half century. Predicted in 1964, the Higgs particle wasn't experimentally confirmed until 2012. Trace the path to this triumph, as physicists narrowed down the properties of the elusive particle and utilized powerful particle accelerators in the hunt.