Search found 942 matches

by Minerva
Fri Apr 06, 2012 3:00 pm UTC
Forum: Science
Topic: Representing chemical formulas as a single number
Replies: 73
Views: 11159

Re: Representing chemical formulas as a single number

I think what you're talking about here sounds more and more like numerological nonsense.
by Minerva
Fri Apr 06, 2012 2:57 pm UTC
Forum: Science
Topic: Basic Thermodynamics Mathematical Witchcraft.
Replies: 21
Views: 4434

Re: Basic Thermodynamics Mathematical Witchcraft.

Another possibility for why they haven't told you the true reason why a bunch of things in thermodynamics are true is that you don't have the tools to understand those reasons yet. Even among physics majors, many stat mech classes are famous for being confusing as all hell and rather impenetrable (...
by Minerva
Fri Mar 23, 2012 5:23 am UTC
Forum: Science
Topic: Worst thing you've seen in a lab
Replies: 256
Views: 233157

Re: Worst thing you've seen in a lab

I'm doing chemistry at uni, and while most people are pretty good, there are some right idiots in the labs at times. The worst I've seen was when my friend had to stop someone from lighting a Bunsen burner in the fume hood THAT WAS USED FOR STORING AND WORKING WITH ORGANIC SOLVENTS! (2nd year organ...
by Minerva
Sat Mar 03, 2012 11:25 am UTC
Forum: Science
Topic: Nitrogen Dioxide as a Second Messenger signal?
Replies: 5
Views: 3039

Re: Nitrogen Dioxide as a Second Messenger signal?

These may be of assistance: http://www.ncbi.nlm.nih.gov/pubmed/16408059 http://www.ncbi.nlm.nih.gov/pubmed/19219851 Nitrite ion in solution is NO 2 - . Saying NO 2 (nitrogen dioxide) when you actually mean NO 2 - (Nitrite ion in an inorganic salt like NaNO 2 ) is pretty bad chemistry. He might have...
by Minerva
Sat Mar 03, 2012 11:09 am UTC
Forum: News & Articles
Topic: IBM quantum computing
Replies: 35
Views: 6346

Re: IBM quantum computing

A quantum computer can only offer certain algorithms for performing certain types of computer science problems (Shor's algorithm for factorisation, or Grover's algorithm for search in an unsorted database) with better computational complexity than any known classical algorithm for doing the same pra...
by Minerva
Wed Feb 29, 2012 2:57 pm UTC
Forum: Science
Topic: Angular Momentum
Replies: 13
Views: 3932

Re: Angular Momentum

An electron can't "absorb" a photon. It might couple to a photon, sure. Also, +1 to previous comments - "spin" is really just a quantum number with a funny name, like strangeness or charm or truth or beauty. It's entirely a quantum-mechanical thing which needs to be learned and u...
by Minerva
Fri Feb 17, 2012 3:52 pm UTC
Forum: Hardware
Topic: NOT Baking Eggs. (Incubator design-PWM question)
Replies: 9
Views: 4710

Re: NOT Baking Eggs. (Incubator design-PWM question)

You can't do PWM with an AC mains signal and expect it to work well. The way that this sort of thing is normally done, say with line-powered AC motor controllers or light dimmers, is to detect the AC zero-crossing point, wait for a carefully controlled time, and delay the firing of the triac until a...
by Minerva
Fri Feb 17, 2012 3:43 pm UTC
Forum: Hardware
Topic: Electronic engineers to the rescue: Some Diodes.
Replies: 4
Views: 2326

Re: Electronic engineers to the rescue: Some Diodes.

Think of two diodes in parallel, but facing opposite directions. Current can pass through it in both directions, so an AC waveform can pass through it, but signal amplitudes less than one forward voltage drop (about 600 mV under typical conditions for silicon) are clamped. Now if you replace the dio...
by Minerva
Thu Feb 16, 2012 10:13 am UTC
Forum: Science
Topic: Would chocolate kill velociraptors?
Replies: 36
Views: 8278

Re: Would chocolate kill velociraptors?

Oh, wait, I know!

If we inject the theobromine into ostrich eggs, and leave them laying around for the velociraptors to eat, that might just work!
by Minerva
Wed Feb 08, 2012 12:30 pm UTC
Forum: Science
Topic: Anti-matter = repulsive gravity?
Replies: 49
Views: 12144

Re: Anti-matter = repulsive gravity?

My understanding is that since gravity is a second-rank tensor field (hence why gravitons are theoretically spin-2) a consequence of that is that gravity can only be attractive, not repulsive. And anyway, haven't we already done plenty of experimental confirmation that antiparticles (including neutr...
by Minerva
Wed Feb 08, 2012 12:24 pm UTC
Forum: Science
Topic: If you want a warm room, does energy efficiency matter?
Replies: 28
Views: 9353

Re: If you want a warm room, does energy efficiency matter?

To give a relevant example which is an accurate example of the point you're trying to make: Suppose you live in a cold climate, and you're usually using the heating in your house, and that heat is provided by a central oil-fired furnace in the basement, or something like that. Suppose that a good po...
by Minerva
Sun Dec 25, 2011 5:44 pm UTC
Forum: Serious Business
Topic: Request for info - UN "first contact" protocol
Replies: 3
Views: 2695

Re: Request for info - UN "first contact" protocol

I don't think we should bother doing this until after we've invented the technology to reanimate Carl Sagan.
by Minerva
Thu Dec 22, 2011 1:50 pm UTC
Forum: Science
Topic: Pauli Exclusion Principle and Brian Cox
Replies: 16
Views: 9062

Re: Pauli Exclusion Principle and Brian Cox

I am sure he checked that this was solid before he said it, because we all know that everybody would be calling him a twat or a "nobber" or (insert name here that he calls crackpots) if he slipped up, and he would never hear the end of it.
by Minerva
Thu Dec 22, 2011 1:46 pm UTC
Forum: Science
Topic: Pauli Exclusion Principle and Brian Cox
Replies: 16
Views: 9062

Re: Pauli Exclusion Principle and Brian Cox

It's one of those quantum-mechanics phenomena that can happen and will happen, but it's so improbable, so subtle or so insignificant that it is interesting and fun and beautiful from a theoretical physics point of view but utterly meaningless in terms of ever having any practical effect on anything ...
by Minerva
Sun Dec 18, 2011 8:28 am UTC
Forum: News & Articles
Topic: Japan declares Fukushima I in cold shutdown
Replies: 10
Views: 2388

Re: Japan declares Fukushima I in cold shutdown

I think this implies that people should be allowed to return home once levels are below 10 mSv/year, although it doesn't say so explicitly. I certainly think they should. For comparison, professional airline pilots and crews get occupational radiation doses of about 5-9 mSv/y on average. Personally...
by Minerva
Sun Dec 11, 2011 3:30 am UTC
Forum: News & Articles
Topic: Iran Captures US Stealth Drone
Replies: 73
Views: 9638

Re: Iran Captures US Stealth Drone

Wasn't there a case earlier this year where people hacked into the video feed of spy drones in Afganistan? They didn't "hack in" to the drones in the "Oh me yarm, they're downloading the garbage file from our kernel" sense. All they did was receive (and then maybe apply a simple...
by Minerva
Fri Dec 09, 2011 10:17 am UTC
Forum: Science
Topic: Electric Shock Machine for Pest Control
Replies: 6
Views: 5839

Re: Electric Shock Machine for Pest Control

I need a plan or circuit to convert 240v to around 60 to 100v AC or DC? If you want it to be adjustable, the easiest way to do it is with a variac. If you want DC, follow the variac with a bridge rectifier and capacitor, remembering that the capacitor must be rated for an appropriately high voltage...
by Minerva
Fri Dec 09, 2011 10:12 am UTC
Forum: News & Articles
Topic: Iran Captures US Stealth Drone
Replies: 73
Views: 9638

Re: Iran Captures US Stealth Drone

Nobody really knows what's going here. You've got what the Iranians are saying to the press vs. what the Iranians really know vs. what the Americans are saying to the press vs. what the Americans really know vs. what the drone's developers are saying to the Americans vs. what the drone's developers ...
by Minerva
Fri Dec 09, 2011 7:05 am UTC
Forum: Science
Topic: What textbooks would you recommend in the following courses?
Replies: 42
Views: 7314

Re: What textbooks would you recommend in the following cour

There's a book I think is good called Modern Physics by Serway, Moses and Myer. It covers modern physics in a more broad but more shallow way. So you've got a bit of quantum mechanics, a bit of special and general relativity, a bit of nuclear physics, radioactivity, a bit of particle physics, atomic...
by Minerva
Fri Dec 09, 2011 6:55 am UTC
Forum: Science
Topic: What is this element: 1s2 2s2 2p6 3p4 4s1 (electron config)?
Replies: 2
Views: 2964

Re: What is this element: 1s2 2s2 2p6 3p4 4s1 (electron conf

Assumption: It is a neutral atom and not an ion which has had electrons added or removed from its normal neutral state?

What's the total number of electrons? 15. So it's phosphorus.

The actual configuration of those electrons does not matter as explained above.
by Minerva
Thu Dec 08, 2011 4:11 pm UTC
Forum: Science
Topic: What textbooks would you recommend in the following courses?
Replies: 42
Views: 7314

Re: What textbooks would you recommend in the following cour

Jackson's Classical Electrodynamics is one of the most highly regarded CED books out there, but it might be a little too "hard" for the lower years of undergrad. Griffiths' Intro to Electrodynamics is a bit easier. Griffith's Introduction to Quantum Mechanics is supposed to be good. Also t...
by Minerva
Wed Dec 07, 2011 7:28 am UTC
Forum: News & Articles
Topic: So... the entire United States is now a battleground
Replies: 142
Views: 18838

Re: So... the entire United States is now a battleground

The OP article is written by infamous anti-science crackpot and conspiracy theorist Mike Adams, of Natural News etc. (in)fame, so forgive me if I don't take this seriously at all.
by Minerva
Wed Dec 07, 2011 7:22 am UTC
Forum: News & Articles
Topic: Voyager 1 Reaches New Region of Space
Replies: 44
Views: 9300

Re: Voyager 1 Reaches New Region of Space

I love the fact that we can still control the Voyagers, and do good science with them today. Absolutely remarkable. In fact, I was reading something from JPL engineers the other day where they said they expect to be able to work with Voyager 2 (in other words, communicate with it, control it, and co...
by Minerva
Mon Dec 05, 2011 11:16 am UTC
Forum: Serious Business
Topic: A question about Fukushima
Replies: 11
Views: 3809

Re: A question about Fukushima

Criticality is not some sort of horrible, terrible, destructive catastrophe. In fact, criticality is the normal, intentional operational state of a nuclear fission reactor. Ideally, criticality is the state that your nuclear power reactor is actually supposed to be kept in all of (or most of) the ti...
by Minerva
Sun Nov 27, 2011 7:14 am UTC
Forum: Serious Business
Topic: US citizen imprisoned without trial 18 months and counting
Replies: 5
Views: 3614

Re: US citizen imprisoned without trial 18 months and counti

I do agree with you with regards to the idea that there should be a fair trial at the soonest practical time and that a person shouldn't be kept imprisoned for years with no trial. Manning's case wouldn't be the first time this has happened to somebody, though. It's nothing new. Kevin Mitnick, for e...
by Minerva
Fri Nov 25, 2011 6:06 am UTC
Forum: Serious Business
Topic: Cancer and low-carb diet - your thoughts?
Replies: 19
Views: 7583

Re: Cancer and low-carb diet - your thoughts?

How similar is this to notorious quack cancer "therapies" that are diet-oriented, such as the Gerson quackery? Here's a straightforward question to ask. Where are the publications that have been submitted and peer-reviewed and accepted and published in the peer-reviewed scientific journals...
by Minerva
Fri Nov 25, 2011 5:46 am UTC
Forum: Science
Topic: Good Physics Read
Replies: 13
Views: 1655

Re: Good Physics Read

An introductory Special Relativity text might be just the thing. It shouldn't have any hard math (single variable calculus maybe), and everything will be explicitly derived. Plus, exercises, if you'd like em! I used French , I bet you can find one used that's affordable. I'm pretty sure John Archib...
by Minerva
Fri Nov 25, 2011 5:45 am UTC
Forum: Science
Topic: Good Physics Read
Replies: 13
Views: 1655

Re: Good Physics Read

Maybe try Lisa Randall's books? I just looked up some of her books, does she give strict mathematical proofs? I don't want to just read another Brian Greene washed down physics book, haha. Well, the thing is, do you want a popular physics book or do you want a physics textbook? If you read physics ...
by Minerva
Fri Nov 25, 2011 5:42 am UTC
Forum: News & Articles
Topic: Education from OWS thread
Replies: 201
Views: 21571

Re: Education from OWS thread

My solution was to remove fields of study that don't lead to employment from the university system You've got to be a little bit careful about that though, otherwise somebody might eventually come along and try to argue that, say, theoretical physics or astronomy or planetary science or quantum fie...
by Minerva
Wed Nov 23, 2011 11:58 pm UTC
Forum: Science
Topic: Good Physics Read
Replies: 13
Views: 1655

Re: Good Physics Read

Maybe try Lisa Randall's books?
by Minerva
Sat Nov 19, 2011 9:44 pm UTC
Forum: News & Articles
Topic: Lighter than Air Solid
Replies: 53
Views: 7698

Re: Lighter than Air Solid

Is it less dense than silica aerogel? If so, it's not the lowest-density solid material :)

Still an interesting material, though, it's like a metal version of aerogel :)
by Minerva
Sat Nov 19, 2011 9:43 pm UTC
Forum: News & Articles
Topic: Neutrinos continue blatant disregard for the law
Replies: 14
Views: 3527

Re: Neutrinos continue blatant disregard for the law

They haven't really changed anything about key aspects of the timing and measurement methodology, though, which were key aspects that many scientists suspected were where the error was introduced.
by Minerva
Thu Nov 17, 2011 6:15 pm UTC
Forum: Science
Topic: Molten salt reactors
Replies: 19
Views: 9809

Re: Molten salt reactors

The Liquid-Fluoride Thorium Reactor (LFTR) doesn't really involve reprocessing in the usual sense. It has chemical processing of the fuel salt closely integrated with the reactor itself, operating all the time. This can be used to manufacture fission-product radionuclides with medical and technologi...
by Minerva
Thu Nov 17, 2011 5:55 pm UTC
Forum: Serious Business
Topic: $131M taxpayer dollars annually to fund quackery
Replies: 31
Views: 6314

Re: $131M taxpayer dollars annually to fund quackery

And as an added benefit, the herbals don't have any of the dangerous side-effects of the drugs she's been on Herbal medicines don't work because they contain magical happy plant powers. Those herbal medicines that actually work (which is the minority of them) work because the plant contains a pharm...
by Minerva
Thu Nov 17, 2011 3:29 am UTC
Forum: Serious Business
Topic: $131M taxpayer dollars annually to fund quackery
Replies: 31
Views: 6314

Re: $131M taxpayer dollars annually to fund quackery

I can't believe anyone would put a chiropractor on the same level as a homeopath. An M.D. prescribing pills sure isn't going to put your bones back where they're supposed to be when you pull something out of place. You need a chiropractor for that. Next you'll be telling me orthodontics is a scam a...
by Minerva
Wed Nov 16, 2011 12:41 am UTC
Forum: Science
Topic: Kelvin vs. Celsius
Replies: 60
Views: 13935

Re: Kelvin vs. Celsius

To get back to something which is maybe more practically relevant to the OP: If you're performing any kind of physics calculations (such as statistical mechanics, thermodynamics, gas laws etc.) that involve a temperature as one of the inputs, the temperature usually must be converted to Kelvin first.
by Minerva
Thu Nov 10, 2011 10:05 pm UTC
Forum: News & Articles
Topic: IAEA report on Iranian nuclear weapon development
Replies: 285
Views: 22944

Re: IAEA report on Iranian nuclear weapon development

Also, it should be noted that Iran does have a method of delivering a nuclear payload to Israel: the Shahab 3 rocket. There's a big, big difference between inventing a big, heavy nuclear weapon that you can deliver in a truck, like the Trinity Gadget, and developing a highly-developed nuclear weapo...
by Minerva
Thu Nov 10, 2011 8:45 pm UTC
Forum: News & Articles
Topic: IAEA report on Iranian nuclear weapon development
Replies: 285
Views: 22944

Re: IAEA report on Iranian nuclear weapon development

Youre right, except about the decade bit. Thing is that Israel cannot take the risk that Iran won't use them. Therefore Israel must stop them from acquiring them. But Israel and Israel's allies have lots of nuclear weapons and Iran doesn't have nuclear weapons. So, right now, the main risk is Iran ...
by Minerva
Thu Nov 10, 2011 8:38 pm UTC
Forum: Science
Topic: Can we make our own set of physics homework questions?
Replies: 14
Views: 2795

Re: Can we make our own set of physics homework questions?

LaserGuy wrote:Bugs Bunny had to calculate something in carats per barn-yard.


The density of a neutron star is roughly 0.32 microcarats per barnyard :)
by Minerva
Wed Nov 09, 2011 5:05 pm UTC
Forum: Serious Business
Topic: Consequences of attacks on nuclear facilities
Replies: 3
Views: 1501

Re: Consequences of attacks on nuclear facilities

One suspects that the explosive disruption of thousands of centrifuges would create a substantial plume and the response of the nation on the receiving end of that plume might be worth anticipating. In that case it's only uranium, so it's not particularly dangerous at all. Contrary to popular belie...

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