Category Archives: Physics

Slide Rule Examples

John F. Lindner April 14, 2022 11:30 AM

Slide rules were widely used in engineering, science, and mathematics until the early 1970s, including during the Gemini and Apollo space programs. Although rendered largely obsolete by the advent of inexpensive electronic calculators, their descendants continue to have specialized applications, such … Continue reading →

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Diffraction Limited

John F. Lindner March 17, 2022 11:41 AM

Yesterday, Webb optical telescope element manager Lee Feinberg said “We made the right telescope” while reporting that its focus has reached the  diffraction limit of 0.7 arcseconds at the infrared wavelength of 2 microns. (For comparison, from Earth, Luna subtends … Continue reading →

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Halo Orbit

John F. Lindner February 7, 2022 5:43 PM

The Webb telescope has fully deployed and arrived at its halo orbit about the second Earth-Sun Lagrange point. But how can it orbit an empty point in space? In the accompanying animated sequence of inertial space diagrams, a star (red) … Continue reading →

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50 years later

Niklas Manz January 7, 2022 3:35 PM

After MANY months of not traveling, I scheduled a meeting with Robert (Bob) M. Mazo, Professor emeritus from the University of Oregon, now living outside Philadelphia. In 1971/1972 he helped developing the key model to describe chemical reaction-diffusion systems. But, … Continue reading →

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Burning Plasma

John F. Lindner December 9, 2021 3:20 PM

In August I received an urgent email from my brother with the title “Fusion”. The National Ignition Facility (NIF) had created a burning plasma — a star on Earth — a major milestone on the long road to controlled nuclear fusion. … Continue reading →

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Dandelin Spheres

John F. Lindner September 6, 2021 9:11 PM

In 1609, Johannes Kepler first described how planets orbit the sun in ellipses. Kepler understood an ellipse as both the locus of points whose distances from two foci sum to a constant and as the intersection of a cone and a plane. But how … Continue reading →

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For Teague

John F. Lindner August 25, 2021 6:39 PM

Sadly and unexpectedly Wooster physics senior Teague Curless ’22 died yesterday. I was fortunate to teach Teague some physics, especially in my Nonlinear Dynamics class last spring. Teague’s semester project beautifully illustrated chaos in a double pendulum — a pendulum swinging … Continue reading →

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Spinors

John F. Lindner August 5, 2021 9:10 PM

Fermions like electrons, protons, and neutrons inhabit a 720° world: 360° rotations negate their quantum states, but 720° rotations restore them. A simple macroscopic model of such spinors is an arrow translating on a Möbius strip: as the center circle rotates, … Continue reading →

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Transition

John F. Lindner June 30, 2021 7:55 AM

As I transition to emeritus status tomorrow, I reflect on 33 years at Wooster. I am thankful for the freedom I’ve had to design my own courses, including eight first-year seminars; for the flexibility to explore a wide range of … Continue reading →

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Free-Fall Spinning Tunnels

John F. Lindner April 28, 2021 9:01 PM

Jump into an evacuated hole drilled straight through a uniform, static Earth-like sphere. Accelerate to 7.9 km/s (or 18 000 m.p.h.) at the center, then decelerate back to zero at the antipodes 42 minutes later! Step out of the hole upside down — … Continue reading →

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