Physik im Prater

prater_2011Last week, I was in Vienna, invited to talk about Physik im Prater und auf dem Spielplatz at the 70th annual “Fortbildungswoche für Lehrkräfte aus Physik und Chemie”, arranged by “Der Verein zur Förderung des physikalischen und chemischen Unterrichts

I made sure that I arrived to Wien in time to do some research before the presentation, to know which examples would be relevant, take some ride photos, and, of course, collect ride data from the PraterTurm, as complement to the data in the recent paper about Rotating Swings – a Theme with variations.

The walk towards the PraterTurm passes many other rides, starting with the classic Riesenrad, and a few entangled roller coasters. The photo below shows clearly the saw-toothed track part of the “anti-rollback” device, which causes the familiar click-click sound as the roller coaster train ascends the lift hill.uppdrag Continue reading


Clockwise or Counter-Clockwise: On Carousels and Cats

Which way do carousels move?

"Finkarusellen" from Tusenfryd, reversed"Finkarusellen" from Tusenfryd, Oslo

As I walked towards UNESCO for the second day of the opening event of IYL2015, I discovered two carousels on different sides of the Seine, moving in opposite directions – counter-clockwise on the right bank and clockwise on the left bank, just northwest of the Eiffel tower.
It reminded me of spectacular quantum physics experiment where a beryllium ion was prepared in a superposition state with itself, with “50 percent probability of being in a “spin-up” state in its initial position and an equal probability of being in a “spin-down” state in a position as much as 80 nanometers away, a vast distance indeed for the atomic realm. In effect, the atom was in two different places, as well as two different spin states, at the same time” (Scientific American, 1996). This beryllium ion is such a spooky illustration of the quantum world, “an atomic analog of a cat both living and dead”, i.e. “Schrödinger’s cat”, and was part of the motivation for the Nobel prize in physics 2012, shared by Dave Wineland and Serge Haroche. Continue reading

Cold fusion haunts again

A few days ago, I was asked by the Gothenburg university magazine, GU Journalen, to comment on an article “How science goes wrong”: In view of recent Swedish media attention about Andrea Rossi and his E-cat, I decided to connect back to the Cold Fusion events from 25 years ago. Shortly after that publication in the Wall Street Journal, I was back at the University of Washington, where I had been a post-doc a few years earlier, and had the opportunity to listen in on some of the cold fusion discussions there. 

I am sorry – the rest of this post is in Swedish.

Den kalla fusionen går igen

Våren 1989 publicerade Wall Street Journal på förstasidan överraskande resultat om kall fusion av Pons och Fleischman. Resultaten väckte stor internationell uppmärksamhet och många forskargrupper försökte reproducera och förstå resultaten – som naturligtvis skulle ha stor betydelse för världens energiförsörjning, om de kunde bekräftas. American Chemical Society planerade en session om kall fusion under sitt årsmöte 1989. Lite senare samma vår besökte jag Institute for Nuclear Theory, vid University of Washington i Seattle, där jag tidigare varit post-doktor. Jag fick höra att den experimentella kärnfysikgruppen hade fått ett bidrag till denna session refuserat – med motiveringen att eftersom de inte hade sett någon effekt så hade de inte något relevant att bidra med.

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