1

Physics, Astronomy & Cosmology / Re: Has E=mc2 been proved practically?

« Last post by Bored chemist on Today at 14:47:28 »

So we need to rethink how we visualise electricity and the parameters surrounding photons inside a conductor.

Can we start that "rethinking" process by realising that the photons are outside the conductor.
You can verify that fairly simply.
The speed of a signal down an insulated cable depends on the refractive index of the insulation.

If you didn't know that, it shows that you don't know what you are talking about...

2

The Environment / Re: The link between global warming and world population expansion.

« Last post by Bored chemist on Today at 14:44:23 »

we simply ... and abolish all child benefits.

In anything like a democracy, that's not going to be simple is it?
You seem to have forgotten that children already exist.

3

The Environment / Re: The link between global warming and world population expansion.

« Last post by alancalverd on Today at 14:33:47 »

There's a huge difference between compulsion and persuasion.  To implement the policy in the UK, we simply pay every woman UKP500 (why no sterling pound sign on this site?) every 6 months if she isn't pregnant, and abolish all child benefits. UKP1000 per year for doing nothing seems like a good offer to any teenager and 20 years of selfimposed poverty seems like an unacceptable alternative.

The Chinese experiment was confounded by an underlying cultural preference for male children,. which led to all sorts of infanticides and hidden children.

Whether anyone else follows suit is up to them, but the advantages should be obvious. It didn't take any persuasion to get the rest of the world to adopt the steam engine, jet engine, penicillin, pneumatic tyre, worldwide web......

There's no great hurry. The climate will become unacceptable  for most folk within the next 100 - 500 years, but a significant reduction of population will at least mitigate the harm for our successors and in most cases will lead to a sustainable economy that is not entirely beholden to foreign scum. 

4

The Environment / Re: The link between global warming and world population expansion.

« Last post by paul cotter on Today at 14:11:45 »

Alan, I think you know by now that I agree 100% with your analysis re population. The problem I see is getting sufficient buy-in for such reduction measures, especially from the female of the species. China tried the one child policy which had mixed results, however being such an authoritarian regime it was relatively simple to decree but it led to abuses. In a free country it is much more difficult as a large cohort of females will value a bunch of sprogs above monetary gains.

5

Science Experiments / Re: How to demonstrate polarization of light?

« Last post by hamdani yusuf on Today at 12:55:53 »

Light Interference versus Polarization

In this demonstration, a Michelson-Morley Interferometer is used to create an interference pattern between a beam of light with itself.  This interference seems to be abolished when one ray's polarization is rotated by 90 degrees.

This video can save me money, time and effort to demistify experimental results with light.

6

Physiology & Medicine / Re: Wintertime and Hand Washing. Whose Directions Do You Follow?

« Last post by Bored chemist on Today at 12:35:36 »

Worth reading the instructions on the tin. Once the Swarfega has emulsified the barrier cream, you wash it off.

You suggest it's a 2  or 3 stage process.
The instructions give 4.
"? Apply small amount directly to soiled hands
? Rub in to loosen dirt
? Add a little water and continue rubbing
? Rinse with plenty of water and dry thoroughly"
From
https://www.deb-disposables.co.uk/files/ww/SWA157A_info.pdf

Did you read them?

In any event, you are ignoring the fact that the stuff does emulsify skin oils along with the barrier cream because it can't tell the difference.
That's why Paul says it does.

7

Physiology & Medicine / Re: Wintertime and Hand Washing. Whose Directions Do You Follow?

« Last post by alancalverd on Today at 11:58:33 »

Worth reading the instructions on the tin. Once the Swarfega has emulsified the barrier cream, you wash it off. Basic principle of surfactants. Problem is that practically everyone uses far more surfactant than they need, which is good for detergent manufacturers but not for the skin or the environment.

8

Physics, Astronomy & Cosmology / Re: Has E=mc2 been proved practically?

« Last post by alancalverd on Today at 11:55:12 »

Not "we", just you. Inventing absurdities does not advance understanding: a basic textbook might.   

9

New Theories / Re: Why light changes its speed and direction during refraction?

« Last post by hamdani yusuf on Today at 11:54:02 »

https://en.m.wikipedia.org/wiki/Sellmeier_equation

The Sellmeier equation is an empirical relationship between refractive index and wavelength for a particular transparent medium. The equation is used to determine the dispersion of light in the medium.

Refractive index vs. wavelength for BK7 glass, showing measured points (blue crosses) and the Sellmeier equation (red line)

The X-ray should be on the left in the diagram.
The equation is pretty good at predicting the refractive index. Unfortunately, the article doesn't show it's theoretical derivation.

10

The Environment / Re: The link between global warming and world population expansion.

« Last post by alancalverd on Today at 11:50:36 »

Beg to differ! The point is that people generally aspire to  something like a Western standard of living, with clean water on tap, adequate food safely stored and distributed, easy personal transport over significant distances, and control over indoor ambient temperature.

To  achieve this in a fertile, temperate place like the British Isles requires an average of 5 kW of "artificial" energy per capita. You might get away with a bit less in some subtropical coastal regions (say the north Mediterranean) but anywhere more continental, more polar, or more equatorial, demands up to twice that amount (see the date for Singapore - high rise buildings in a hot, humid environment need a lot of aircon).

Problem is that

(a) we cannot produce  400 GW sustainably in these windy islands

(b) even if you could generate an average of 5 kW per capita in the places where most people live, there is no storage and distribution infrastructure, industrial or transport powerplant for anything other than liquid fuels or coal.

But we can control the number of capitas that demand the power. By simply reducing births to one per female, you reduce the population by a factor of 5 in 100 years and everyone is better off.