Tablets for creativity and science - and the raspberry Pi

There are now many affordable and even out right cheap tablets - computers with touch screens ...

A Strange Question On Cosmic Microwave Background Radiation.

I just ask. If I look at a glowing something with an antenna, I will not get any signal, I think...

As Is Well Known About Lissajous Curves And Ellipses

This is a continuation of "As is well known about elliptic trajectories" where I have put it as...

As Is Well Known About Elliptic Orbits

When we teach, and even communicate with people whom we assume to belong to some sort of common...

User picture.
picture for Hank Campbellpicture for Helen Barrattpicture for Evgeni Starikovpicture for Sascha Vongehrpicture for Ghunshyam Kumar Rogbeerpicture for Steve Donaldson
Ladislav KocbachRSS Feed of this column.

Born in Prague (CZ), studied physics. Started with algol programming on GIER-1 in Rez of the shell model of nuclei in 1966. Moved to Bergen, Norway. Dr. philos. in 1977, atomic collisions, ionization... Read More »

Talking about relativity one should not forget Galileo's great contributions to - or perhaps in fact foundations of - physics. But more fun are Galileos researches on falling bodies and motion of projectiles, all mainly carried out by either real or Gedanken-experiments, the historians are not quite sure there.

But these Galileo experiments have been realized later and are both on YouTube and in Italian museums. 

Here is a schematic picture, the rolling ball will produce regular bell sounds.

I am taking part in discussions with Sascha Vongehr about the MIT video - here on this site -
Falling Faster Than Freefall: A Lesson In Didactics And Critical Thinking.

I have played with the problem in a toy simulator  ( see PHUN (download), scroll a bit down) and have fun..

From my post there:
I am sorry, this is not yet supposed to be published, but I also do not want to delete the content. This is work in progress, somehow the option to keep an "yet unpublished version" disappeared.
You are thus welcome to follow my editing process (the version you read
now is already somewhat complete, but still not well organized).

In part one I promised to show that the trilobite molecule does not look at all like a trilobite but rather as a pine cone. I had some pictures, I wanted to upload them for later editing - but here it all became public.

Here is the Physics News original message with the trilobite molecule:
Ten years ago the trilobite molecule came into the Physics media, like Physics News, Physical Review focus etc. It reappeared about a year ago, in fact in Nature. I am planning to demonstrate here that the trilobite molecule is not at all trilobite-like, it is much more pine-cone like.
I have been again teaching two subjects where electric and magnetic phenomena are important (atomic physics and solid state physics) and met naturally new students. I always tell about the SI system and its history, but ask the students to use "for thinking" the Gaussian-like system (Carl Friedrich Gauss 1777 – 1855, portrait from Wikipedia) , where there is either a strength constant, or the units of charge are defined so that one gets the force as product of the two charges divided by distance. Potential, field energy density and all that are then simply expressed through the field strength, charge, etc, there is definitely no 
I start my activity on these pages by pointing to a security problem we have here. I found it when viewing one of my comments to a news article where a new comment appeared:
I thus wrote there this, which indeed is unfortunately true:
The comment by Tiffany is a spam. It only says "Nice" but points to some shop with cheap bracelets. Tiffany should be removed and then one can remove also this comment.

I would think that it should not be possible to insert a link into the signature.

This is opening this site to miscreants
who could link us to phishing sites. This should be fixed!