Kommentare für Observations

Kommentar zu Special Theory of Relativity – Simplified von Hans Martin Sauer

Hans Martin Sauer — Thu, 30 Apr 2026 09:30:04 +0000

Dear Professor Grothmann,
Thank you very much for presenting this interesting topic. As a former lecturer in physics and mechanical engineering I had the frequent pleasure to explain students exactly that point, that time distances are different for moving observers.
My argument, summarizing Moreley and Michelson, was that physical (and any other natural) processes do not strictly depend on the time which each of us can measure on her/his watch, but on a measure called space-time-distance. In essence, M & M found that no physical process does proceed on the wave front of a beam of light. Here, everything is frozen, and space-time-distance stays 0 forever. Calculating our space-time-distance s to some future or past event which we observe at distance 3-vector {\vec r} at time t should respect this finding.
s is thus the root of the scalar product of the 4-vector (t, {\vec r}) with its space-mirrored counterpart (t, -{\vec r}), which is s = \sqrt{t^2 – r^2}. (I redefine the speed of light c to 1 here).
Usually, this is the instant where I can see the jaws of the young engineers in the lecture room drop. „Is he got crazy?“ I can very well feel with them as I have killed their well-educated confidence in the engineer’s intuition. It is then time to take ruler and pencil, to draw a local orthonormal coordinate frame with space and time axes (that’s what engineers and constructioners are really well-trained in), to draw the light cone and the hyperbolas of constant space-time-distance, and the trajectory of a moving object. It is then a pleasure for me to answer all the usually very intelligent questions from the audience.

Best regards
Hans Martin Sauer, retired member of TU Darmstadt

Kommentar zu Average Waiting Times and 42 von Exit Times and Probabilities – Continued – Observations

Exit Times and Probabilities – Continued – Observations — Sat, 21 Feb 2026 10:12:02 +0000

[…] wrote about the interesting problem of average waiting times here. Inspired by a YouTube short video, I like to continue with a similar problem. I was thinking about […]

Kommentar zu A ChatGPT Letter written by to Myself von michiel van adrichem

michiel van adrichem — Sun, 23 Nov 2025 17:18:13 +0000

“ Surely You’re Joking, Mr. Feynman!“: Adventures of a Curious Character

See: https://en.wikipedia.org/wiki/Surely_You%27re_Joking,_Mr._Feynman!

I have remarks to make. And on deeper philosophies. But probably will send you a separate letter (.pdf)
It forces me to think before I write.

Kommentar zu The Two Envelopes Problem von Paradoxes in Probability Theory – Observations

Paradoxes in Probability Theory – Observations — Fri, 28 Feb 2025 15:10:30 +0000

[…] theory is always a more difficult topic than it seems at first sight. In another posting, I talked about the „two envelopes problem“ and described my basic approach to explain […]

Kommentar zu Suggestions on Math Education von Heinz Roitner

Heinz Roitner — Mon, 11 Nov 2024 12:34:17 +0000

I am approaching 61 and have dealt with (applied) mathematics as teacher in high schools and universities and worked in industry for 20 years. I still hold dear an axiom which goes back to St Thomas Aquinas (800 years ago):
„Nothing is in the brain which has not been in the senses before.“ Preferably, ALL SENSES.
For mathematics that means to me: practice calculations and drawings BY HAND extensively up to an age of 14.
Only then you may use calculators or (mathematical) software.

Kommentar zu What does a Mirror Flip? von Jürgen Buntrock

Jürgen Buntrock — Sun, 24 Mar 2024 12:35:56 +0000

Physics Girl made a Video about this subject:
https://www.youtube.com/watch?v=vBpxhfBlVLU

Kommentar zu DOF Calculator in Python von Alexandre

Alexandre — Tue, 30 Jan 2024 11:18:57 +0000

Hello
In bokeh function you use L
return 2*F**2/(A*(D-L))/math.sqrt(0.024**2+0.036**2)
But it isn’t defined

Kommentar zu Suggestions on Math Education von admin

admin — Sun, 30 Jul 2023 16:52:34 +0000

Als Antwort auf Franz Lemmermeyer. Ich weiß nicht, was Sie meinen.

Kommentar zu Suggestions on Math Education von Franz Lemmermeyer

Franz Lemmermeyer — Sun, 30 Jul 2023 08:38:25 +0000

„This starts in primary classes, where calculators replace the external drill of written computations. Later, we should start to ask ourselves if extensive skill and practice in tricks of calculus is really needed any longer. Low-level computations in the head and an understanding of the sizes of numbers (which most people lack) looks more important to me. “

Von einem Mathematiker hätte ich erwartet, dass er einen Denkfehler dieser Größenordnung sieht. Si tacuisses . . .

Kommentar zu Die indische Elite-Auslese von Rene Grothmann

Rene Grothmann — Tue, 09 May 2023 08:32:52 +0000

Als Antwort auf W. Reinhard.

Hier noch ein Link zum Thema:

https://awblog.at/bildungspolitische-perspektiven/