Search found 55 matches

by wbeaty
Wed May 03, 2017 9:23 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1818: "Rayleigh Scattering"
Replies: 99
Views: 27569

Re: 1818: "Rayleigh Scattering"

There are, however, numerous misconceptions in your response. I'll try to address them one by one. Heh, and fail! First, red illumination is not an analogy for the sky. Instead, shine white light in a fog-filled room with black-painted walls, and observe a bright blue color. The fog is the origin o...
by wbeaty
Sun Apr 02, 2017 7:30 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1818: "Rayleigh Scattering"
Replies: 99
Views: 27569

Re: 1818: "Rayleigh Scattering"

Agreed, Randall messed up here. Air is not blue; it's colorless. Nope. You've got the very misconception that this comic is designed to fight. Without air, the sky would be black. Ask yourself what material up there is colored blue? Not "sky." It's the thick air layer. Sunlight shines on ...
by wbeaty
Sat Apr 01, 2017 12:48 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1818: "Rayleigh Scattering"
Replies: 99
Views: 27569

Re: 1818: "Rayleigh Scattering"

WHERE DOES RANDALL GET THIS STUFF? Two of them are my own memes: "The sky is blue because air is blue," and "airfoil lifting-force misconception" come from http://amasci.com/miscon/miscon4.html#mis , injected into various Newsgroups in the early 1990s, then finally on www 3/1995....
by wbeaty
Fri Oct 05, 2012 4:39 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1117: "My Sky"
Replies: 58
Views: 16143

Re: 1117: "My Sky"

In very late afternoon, stand outdoors and stare straight upwards into the deepest blue. Now spin around fast while still looking up. If you don't get dizzy and crash into stuff, in the exact center of your vision you'll notice a dim yellow hourglass shape which doesn't rotate. " Haidinger's br...
by wbeaty
Wed Aug 15, 2012 11:16 pm UTC
Forum: What If?
Topic: What-if 0007: "Everybody Out"
Replies: 350
Views: 63335

Re: What-if 0007: Everybody Out

A continuous form of reaction would be very nice, yes. However, we have not been able to develop it (cold fusion) yet. Continuous reaction is called "nuclear reactor?" Continuous reaction with propellant is called NERVA http://en.wikipedia.org/wiki/NERVA Then there's the extremely nasty g...
by wbeaty
Wed Aug 15, 2012 10:56 pm UTC
Forum: What If?
Topic: What-if 0007: "Everybody Out"
Replies: 350
Views: 63335

Re: What-if 0007: Everybody Out

Anyway, I was short of wonder-struck by the scientific revelations of this one - I could have more arrived more or less the same conclusions myself - but my fascination with atomic spaceflight was once again rekindled by the mention of Project Orion. There is a film about it ( http://www.imdb.com/t...
by wbeaty
Mon Aug 13, 2012 9:05 am UTC
Forum: What If?
Topic: What-if 0006: "Glass Half Empty"
Replies: 94
Views: 44191

Re: What-if 0006: Glass Half Empty

So... Construct a glass that is segmented with a thin-but-vacuum-resistant seal between the top and bottom halves. Fill the top half with water, and create a vacuum in the bottom half via a small hole and pump. Then, using a weight or something similar, shatter the seal between the two layers. Yep,...
by wbeaty
Thu Aug 09, 2012 3:03 am UTC
Forum: What If?
Topic: What-if 0006: "Glass Half Empty"
Replies: 94
Views: 44191

Re: What-if 0006: Glass Half Empty

Wrong. You can get the water hammer effect by hitting the beer bottle just right. You CAN'T get a vacuum-suction-glass-to-the-ceiling-launcher by hitting a beer bottle just right. You'd just have to hit the beer bottle much, much harder (probably destructively hard.) It won't be exactly identical, ...
by wbeaty
Wed Aug 08, 2012 1:50 am UTC
Forum: What If?
Topic: What-if 0006: "Glass Half Empty"
Replies: 94
Views: 44191

Re: What-if 0006: Glass Half Empty

The impact from the water will go almost entirely into fracturing the glass. Not true. Brief experimentation with beer bottles and mallets shows that we don't need a vacuum pocket many-cms thick in order for the water to fracture the glass bottom. Crude estimate from experience: 1/2cm pocket can do...
by wbeaty
Wed Aug 08, 2012 1:29 am UTC
Forum: What If?
Topic: What-if 0006: "Glass Half Empty"
Replies: 94
Views: 44191

Re: What-if 0006: Glass Half Empty

I think the glass lifting itself is debatable, however. Imagine a spring-powered gun, where the spring provides 100lb 450nt force, and the bullet is a 0.5LB 0.3KG hunk of water. What's the muzzle velocity? Will the gun fly backwards when fired? Will it launch itself upwards if fired down (assume th...
by wbeaty
Wed Jul 11, 2012 9:07 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1080: "Visual Field"
Replies: 129
Views: 30435

Re: 1080: "Visual Field"

The keyword everyone is really after: ENTOPIC http://en.wikipedia.org/wiki/Entoptic_phenomenon http://en.wikipedia.org/wiki/Blue_field_entoptic_phenomenon or "Sheerers" The blue-yellow-quadrants polarization thing is found under http://en.wikipedia.org/wiki/Haidinger%27s_brush Back before ...
by wbeaty
Mon Jun 11, 2012 8:46 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1067: "Pressures"
Replies: 75
Views: 166153

Re: 1067: "Pressures"

ALT TAB! I wonder if Albert kept his personal work sitting open in his top desk drawer, then pushed it closed whenever the boss walked by. BJT story: Bardeen and Brattain had been ordered to stop working on their transistor and to concentrate on the FET as before. So they loaded the experiment onto ...
by wbeaty
Thu Mar 29, 2012 6:40 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0941: "Depth Perception"
Replies: 214
Views: 164331

Re: 0941: "Depth Perception"

No stereo goggles needed. Go do it right now: all you need is a few minutes worth of video shot from a plane. Notice that recordings of horizontally moving scenery are full of stereo images. On a plane, one second video delay at 500MPH is 733ft stereo lens separation - Shoot some footage of distant ...
by wbeaty
Fri Oct 14, 2011 6:35 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0941: "Depth Perception"
Replies: 214
Views: 164331

Re: 0941: "Depth Perception"

There's no app for this yet? After all, all you need is software. And any video shot from a side window in an aircraft, or even a car. No? The frames? Time sequence is lateral position sequence? OK, take a video stream and sample it from two places about 1sec apart. If your cross-country flight was ...
by wbeaty
Wed Aug 03, 2011 4:46 pm UTC
Forum: Science
Topic: Electronics for Alien Minds
Replies: 5
Views: 3543

Re: Electronics for Alien Minds

Weird A-field trivia: Carver Mead wrote a 'crackpot physics' book where A-fields play a significant role: COLLECTIVE ELECTRODYNAMICS: QUANTUM FOUNDATIONS OF ELECTROMAGNETISM, Mead 2002 http://www.pnas.org/content/94/12/6013.full http://www.math.umb.edu/~sp/mead.pdf http://www.amazon.com/Collective-E...
by wbeaty
Wed Aug 03, 2011 1:10 am UTC
Forum: Science
Topic: Electronics for Alien Minds
Replies: 5
Views: 3543

Re: Electronics for Alien Minds

Cool! :) Remember, B is the curl of A by definition. Other good stuff: Twenty Three Years: The Acceptance of Maxwell's Theory JC Rautio, MICROWAVE JOURNAL 50th commemorative http://www.sonnetsoftware.com/support/downloads/publications/MWJ_AcceptanceOfMaxwellsEquations.pdf WP and hyperphysics have ni...
by wbeaty
Mon Jun 13, 2011 8:43 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0911: "Magic School Bus"
Replies: 116
Views: 28220

Re: 0911: "Magic School Bus"

WP batteries entry?! Ms. Frizzle does it right. Much better than paper science textbooks. Fewer "game of telephone" textbook authorship problems. K-6 textbooks never mention that the path for current goes *through* the battery and back out again. Their diagrams typically show no current in...
by wbeaty
Fri Mar 25, 2011 1:47 am UTC
Forum: Serious Business
Topic: Traffic congestion
Replies: 72
Views: 11063

Re: Traffic congestion

And individual road users are much more complicated to model than fluid elements. They do not all behave the same even in the same situations, they behave different at different speeds, at different lanes of the road, near junctions, in different weather and visibility, at morning when they are goi...
by wbeaty
Wed Mar 09, 2011 2:53 am UTC
Forum: Science
Topic: Yawning
Replies: 12
Views: 1478

Re: Yawning

As far as I know it's one of those prehistoric instincts. A member of the group yawning signals to be tired and needing a rest, so those around him also yawn to 'pass on the word' in order to convince the group as a whole to rest rather than losing members because they fall behind. Then that explai...
by wbeaty
Wed Mar 09, 2011 2:37 am UTC
Forum: Science
Topic: Why do you love science?
Replies: 38
Views: 8600

Re: Why do you love science?

I love the feeling of epiphany when you realize the principle behind something that effects every day life, I love science because it gives me (Watchmen's) Dr. Manhattan's superpower ability to use mental powers to disassemble any device and spread the components out into a 3D array, delve in and d...
by wbeaty
Wed Mar 09, 2011 2:24 am UTC
Forum: Science
Topic: public misconceptions
Replies: 1073
Views: 149820

Re: public misconceptions

People were dying of mosquito bites. Someone thought, "why is no one buying them nets?" They buy nets. Now they don't die. Actually it went more like this: people were dying of Malaria and Yellow Fever, and MDs repeatedly showed that it was transmitted by mosquitoes. The entire medical es...
by wbeaty
Wed Mar 09, 2011 1:51 am UTC
Forum: Science
Topic: "The battery that isn't a battery" - my own simple theory.
Replies: 37
Views: 9103

Re: "The battery that isn't a battery" - my own simple theor

On Karpen's pile ...estimate the capacity of a conventional battery having the same volume. AA cells can be up in 2000 to 3000 mA-hours. If you draw a significant current from a Karpen pile, how many hours must pass before you find that it has higher capacity than the best modern battery technology?...
by wbeaty
Wed Feb 09, 2011 6:54 am UTC
Forum: Science
Topic: Non-alcoholic Flambe
Replies: 23
Views: 7666

Re: Non-alcoholic Flambe

Hydrogen foam, w/the gas being pumped in by an aquarium airstone or perforated metal tube?

:)

Trouble is, "lecture bottles" of hydrogen are fairly expensive, and welders' hydrogen even more so.
by wbeaty
Wed Feb 09, 2011 6:50 am UTC
Forum: Science
Topic: Dust and stickiness
Replies: 5
Views: 1477

Re: Dust and stickiness

I might not be sticky, it might be charged. Charged after wiping. After being tribo-charged by contact with an insulator, the electrostatically charged floor attracts the neutral dust particles by induction. This is a phenomenon familiar to owners of vinyl records. The presence of surface charge can...
by wbeaty
Wed Jan 19, 2011 8:22 am UTC
Forum: Science
Topic: Piezoelectric Questions
Replies: 3
Views: 877

Re: Piezoelectric Questions

3) This is the one i'm most interested about. Would going into the nano-level help boost efficiency of piezoelectric materials? Would a block the size of an ipod classic with 100 layers of micro crystals perform better than a solid block of crystal? is yes, how much better would it be? It gives the...
by wbeaty
Wed Jan 19, 2011 7:52 am UTC
Forum: Science
Topic: The Most Sciencey-Sounding Word/Phrase You've Heard
Replies: 176
Views: 34312

Re: The Most Sciencey-Sounding Word/Phrase You've Heard

The microwave tube relies on nonlinear density wave processes in particle streams interacting with solid conductive tuned cavity surfaces. That's right, they are identical to that bizarre resonant-cavity standing wave acoustic source known as the EMPTY BEER BOTTLE.
by wbeaty
Wed Jan 19, 2011 7:49 am UTC
Forum: Science
Topic: Aluminum foil in a microwave - when should you be worried?
Replies: 24
Views: 13814

Re: Aluminum foil in a microwave - when should you be worrie

Common insurance claim for microwave kitchen fire: sparks inside unattended microwave oven set fire to paper also inside microwave oven. Bits of burning paper spew out the rear vent, land in trash can placed under microwave shelf. Big flames. The electric arcs inside your oven aren't necessarily bad...
by wbeaty
Wed Jan 19, 2011 7:02 am UTC
Forum: Science
Topic: Favorite home experiments
Replies: 590
Views: 475237

Re: Favorite home experiments

He took a Kosher Dill Pickle, and a lamp cord. Stripped the ends of both sides of the cord, jammed them in opposite ends of the pickle, and then plugged it in. It glowed a very bright light purple/pinkish color Youtube search: http://www.youtube.com/results?search_query=electric+pickle Here's anoth...
by wbeaty
Wed Jan 19, 2011 6:51 am UTC
Forum: Science
Topic: Favorite home experiments
Replies: 590
Views: 475237

Re: Favorite home experiments

If you move slowly, you can escape from a giant pool of non-newtonian cornstarch goop. Or you can run rapidly across the surface without sinking. But if someone zaps you with a VandeGraaff generator, the cornstarch "hardens," and it stays that way until you discharge. So in theory, you sho...
by wbeaty
Wed Jan 19, 2011 6:36 am UTC
Forum: Science
Topic: Capacitors, AC and DC confusion
Replies: 11
Views: 3345

Re: Capacitors, AC and DC confusion

Capacitors: feed them a constant current, and the voltage between their terminals will rise constantly. Or feed them a smoothly rising voltage, and they'll draw a constant current. Of course with some, you can feed them twenty amps, and the voltage changes reeeeeeally slow: 3,000 Farad Ultracapacito...
by wbeaty
Mon Oct 25, 2010 5:42 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

PS, in all of my stuff above, and in this message, don't take anything as being literally correct textbook stuff. I'm trying to work out a method to correctly explain viscous vortex airplane flight without using any math. I might be blind to a huge flaw that screws everything up. Someone here might ...
by wbeaty
Mon Oct 25, 2010 4:33 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

As I understand it, vector "flux lines" of aerodynamic forces must terminate on vorticity sheets associated with surfaces (as with a venturi,) or must be associated with free regions of vorticity, as with propulsion by vortex-shedding. I think you're thinking of Helmholtz's theorems . If ...
by wbeaty
Mon Oct 25, 2010 3:49 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

Sorry for not answering. Too easily distracted! Nope, instead they explain the flight of infinitely-wide wings. They're a very useful shortcut in calculation, but they offer no explanation. To explore the hidden flaw in infinite-wingspan diagrams, just ask yourself where the other end of the 3rd-law...
by wbeaty
Thu Oct 21, 2010 7:48 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

I'm sorry to disagree there. But the full answer will need more time than I have today, so you'll have to wait. Very understandable! I barely have time to work on this myself. But I'm repeatedly sucked in because there exists a very irritating hole in my connected mental concepts. Dangling chemical...
by wbeaty
Thu Oct 21, 2010 7:23 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

Ahhh.... I think I understand your problem. A bit. No, the force that the air you pushed around exerts on the ground does not "suddenly" go to zero. It gradually goes to zero. Bingo, that's the problem ...because in a 2D world the net force on the ground doesn't gradually go to zero. It d...
by wbeaty
Fri Oct 15, 2010 8:07 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

Ahhh.... I think I understand your problem. A bit. No, the force that the air you pushed around exerts on the ground does not "suddenly" go to zero. It gradually goes to zero. Bingo, that's the problem ...because in a 2D world the net force on the ground doesn't gradually go to zero. It d...
by wbeaty
Fri Oct 15, 2010 7:22 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

As I said in my last post, there is no boundary surface in 2D potential flow diagrams... Oops, I posted a brief msg while working on a response to your earlier one. My words aren't clear enough so we need diagrams, perhaps an animation! Seriously. In the mean time here's the Anderson/Eberhardt expl...
by wbeaty
Thu Oct 14, 2010 8:01 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

The proponents of the arguments usually fall into two camps: (1) those who support the "Bernoulli" position that lift is generated by a pressure difference across the wing, and (2) those who support the "Newton" position that lift is the reaction force on a body caused by deflec...
by wbeaty
Mon Oct 11, 2010 8:27 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

Someone needs to compile a list of things they actually still teach in schools, even just in the lower grades, that are blatantly wrong. If we go through these lists of common student misconceptions, we'll find some which teachers believe too, and some which are taught by K-6 science texts: http://...
by wbeaty
Mon Oct 11, 2010 6:27 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0803: "Airfoil"
Replies: 243
Views: 100366

Re: 0803: "Airfoil"

The real details of how an object generates lift are very complex and do not lend themselves to simplification. For a gas, we have to simultaneously conserve the I take it that means "No" No, wrong. Yes, all the usual verbal explanations of lift ...basically suck decayed donkey testes. Se...

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