Category: Physics

  • Hot & Cold Electricity

    John F. Lindner

    As I kid, I used to help my dad with electrical wiring projects (among other things). I learned that home electricity was “hot & cold”, like water in pipes — or at least, that’s how I understood the explanation. Later I learned that home electricity uses alternating current (AC) rather than direct current (DC), and…

  • Hamiltonian Flow

    John F. Lindner

    Newton wrote, “My brain never hurt more than in my studies of the moon [and Earth and Sun]”. Unsurprising sentiment, as the seemingly simple three-body problem is intrinsically intractable and practically unpredictable. … If chaos is a nonlinear “super power”, enabling deterministic dynamics to be practically unpredictable, then the Hamiltonian is a neural network “secret…

  • Summer Highlight

    John F. Lindner

    Since the mid 1990s, a highlight of my year has been the Physics Department’s National Science Foundation Research Experience for Undergraduates summer program. Our research assistants come from Wooster and from all over the United States, as detailed in the accompanying bubble chart (where the bubble diameters code number of participants per institution). To date,…

  • Higgs Without Molasses

    John F. Lindner

    Although almost all ordinary mass effectively arises from the kinetic and binding energy of quarks and gluons bound to protons and neutrons in atomic nuclei, the Higgs mechanism does endow some particles like quarks and weakons with intrinsic masses. Here I gently introduce the Higgs mechanism without using loose analogies like vacuum field viscosity. Stationary…

  • Meeting 100+ years of experience in nonlinear dynamics

    Niklas Manz

    I met two scientists for my BZ-history project with a combined age of 177 years. It was a great pleasure and honor to talk to them.

  • Continental Bridge

    John F. Lindner

    I remember looking at a classroom map of Earth and thinking the continents seem like puzzle pieces, especially north and south America in the west and Europe and Africa in the east. I mentally fit them together. Later I learned about continental drift and plate tectonics, driven by gravity and mantle convection, with newborn crust…

  • Table of Nuclides

    John F. Lindner

    As of 2019, we have identified or synthesized 118 distinct elements with Z protons, but about 2900 distinct nuclides with N neutrons (where atom is to element as nucleus is to nuclide). The start of my version of the table of nuclides is below, where number of protons Z increases toward 2 o’clock, number of…

  • Wooster Epicycles

    John F. Lindner

    A vector is the sum of its components, a mechanical vibration is a combination of its normal mode motions, a quantum state is a superposition of its eigenstates, and any “nice” function is a Fourier sum of real or complex sinusoids, . The animation below traces the Wooster W in epicycles of 100 circles-moving-on-circles in the…

  • Redefining SI

    John F. Lindner

    Today the SI (Système international d’unités) base units are redefined. The following are now exact. Memorize these numbers! Cs-133 transition frequency constant  defines the second. Then light speed constant  defines the meter. Then Planck’s constant  defines the kilogram. Then electron charge constant  defines the Ampere. Then Boltzmann’s constant  defines the Kelvin. And Avogadro’s constant  defines the mole. And luminous efficacy constant  defines…

  • Black Hole Radii

    John F. Lindner

    I set the alarm for 8:55 AM. Brutal, but I wanted to watch live the National Science Foundation Event Horizon Telescope news conference. I was expecting the first image of a black hole, and the EHT team did not disappoint. But the black hole was not the Milky Way’s Sgr A*, but M87*, a thousand…

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