Search found 34 matches

by alterant
Sat Feb 28, 2009 5:10 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2927
Views: 693445

Re: Common Questions

I guess the problem I'm trying to comprehend is: if gravity is caused by spacetime distortion due to energy; i.e., is geometric in origin, then whence a particle mediating gravity? Is the graviton a traveling disturbance in geometry or something...?
by alterant
Sat Feb 28, 2009 5:55 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2927
Views: 693445

Re: Common Questions

I have a question. It may have been asked before; I can't find it.
Are general relativity and the particle physics idea of the graviton incompatible? Or am I missing something here?
by alterant
Thu Oct 30, 2008 5:59 pm UTC
Forum: Science
Topic: Water bridge (engineering question?)
Replies: 9
Views: 1528

Re: Water bridge (engineering question?)

Oh, I see. In order to keep the water level constant, the excess water displaced by the boats drains out. That makes sense, except of course that water has to be pumped back in...
Neat.
by alterant
Thu Oct 30, 2008 4:31 pm UTC
Forum: Science
Topic: Water bridge (engineering question?)
Replies: 9
Views: 1528

Re: Water bridge (engineering question?)

My guess is that the bridge is not like a river, in the sense that the bridge has a finite length & finite volume of water. I would imagine a system of locks would move boats on and off of it. If it's a finite length, then there should be a weight limit (because the water level will go up with m...
by alterant
Wed Oct 15, 2008 9:56 pm UTC
Forum: Science
Topic: Science books
Replies: 11
Views: 1962

Re: Science books

Not a book, but Walter Lewin (of MIT) has video lectures on Classical Physics, electromagnetism, and wave phenomena available for free on iTunes and online. Particularly the first two sets of lectures are very informative & interesting to watch. It's old, but I really like "Mathematics for ...
by alterant
Wed Oct 15, 2008 7:56 pm UTC
Forum: Science
Topic: Favorite home experiments
Replies: 590
Views: 466981

Re: Favorite home experiments

# Boiling water without fire # You'll need: water and a syringe (without the needle). # How to do: Put a little water in the syringe (about 1/6 or 1/5 of its volume). Cover the extremity tightly (with the finger, or any other thing you can wonder). Pull the piston as fast as possible. The water wil...
by alterant
Wed Oct 08, 2008 5:20 pm UTC
Forum: Logic Puzzles
Topic: Drowning
Replies: 8
Views: 2108

Re: Drowning

Not to insult or poke fun at your puzzle, but it'd be pretty funny if a guy started calculating this the second he heard someone cry from the ocean. Actually, it's spelled "A-W-E-S-O-M-E". "Help! Help!" "I'm trying to, but hey - do you know how to solve a quartic?" &qu...
by alterant
Tue Oct 07, 2008 1:12 pm UTC
Forum: Logic Puzzles
Topic: Drowning
Replies: 8
Views: 2108

Re: Drowning

Then I decided to take a long break. That's where I decided life's too short as well. :P You both got perfectly good answers, to my mind. I'm simply impressed by the fact that: \frac{\sin(\theta_{air})}{\sin(\theta_{water})} = \frac{v_{air}}{v_{water}} Where theta is measured from t...
by alterant
Tue Oct 07, 2008 4:45 am UTC
Forum: Logic Puzzles
Topic: Drowning
Replies: 8
Views: 2108

Drowning

(Stolen from a problem of Richard Feynman's.) You're walking along a beach when you hear someone cry for help. You look and see there's someone drowning offshore, farther up the beach from where you are. (*)<-- you (0, 3) B E A C H ________________________________________________________ W A T E R (...
by alterant
Mon Oct 06, 2008 1:52 am UTC
Forum: Logic Puzzles
Topic: Coins and Scales ... but not what you think.
Replies: 10
Views: 2412

Re: Coins and Scales ... but not what you think.

Good puzzle! I diagrammed it out using something like a Pascal's triangle and found that all the amounts of money are equally likely; there is no expected value - it could be anything. I did not prove this for the n th case or anything that fancy (only went up to 5 coin drops). This ran ...
by alterant
Fri Sep 26, 2008 2:53 am UTC
Forum: Religious Wars
Topic: Stephen Jay Gould vs Richard Dawkins: The Darwinian Wars
Replies: 93
Views: 21356

Re: Stephen Jay Gould vs Richard Dawkins: The Darwinian Wars

Stem cell research and contraception are more than just scientific questions. They also have a large ethical component. No religious person I've ever met has told me that stem cell research and contraception don't work. They simply express an opinion regarding the moral side of these technologies. ...
by alterant
Thu Sep 25, 2008 5:11 pm UTC
Forum: Religious Wars
Topic: Stephen Jay Gould vs Richard Dawkins: The Darwinian Wars
Replies: 93
Views: 21356

Re: Stephen Jay Gould vs Richard Dawkins: The Darwinian Wars

Here are some reasons why this is an invalid: -Muslim scholars preserved Greek philosophy (the closest thing to science at the time) after the fall of Rome -Once this philosophical knowledge was recovered during the Crusades, it was studied in Christian monasteries -Almost all of the modern foundat...
by alterant
Tue Sep 23, 2008 7:59 pm UTC
Forum: Fit Club
Topic: Shakleton is getting in shape and he needs YOUR help!
Replies: 40
Views: 2848

Re: Shakleton is getting in shape and he needs YOUR help!

I am sort of a sugar-addict. Somebody may have mentioned this already, but try having lots of fruit around & eat it whenever you get a sugar craving. It will get rid of the craving and do you some good in the process. E.g., I like to snack on Coronation grapes (smaller & much tastier than o...
by alterant
Tue Jul 01, 2008 4:42 am UTC
Forum: Mathematics
Topic: Seven in random numbers vs. actual data
Replies: 8
Views: 1964

Seven in random numbers vs. actual data

So I was watching "numb3rs" a while ago (yes, yes, I know! not a good source for math wisdom :) ) and there was something mentioned about how a string of random numbers can be distinguished from actual data by the fact that actual data has less sevens (or is it more). Is this complete &...
by alterant
Thu Apr 24, 2008 9:53 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2927
Views: 693445

Re: Common Questions

This is why I shouldn't be allowed to talk when tired.
I guess half-life seemed odd to me because of this probabilistic aspect of it. Thanks, I'll shut up and go wear the dunce cap now. :P
by alterant
Thu Apr 24, 2008 8:41 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2927
Views: 693445

Re: Common Questions

Okay, another question. I know that if a radioactive substance has a half-life of time T, then if we take any large sample of it and wait for T, there will be half the original amount left. But what does "sample" mean? If I have say 2 kg of a radioactive substance, and put 1 kg in one box,...
by alterant
Sat Apr 12, 2008 5:40 am UTC
Forum: Science
Topic: About the Drake Equation...
Replies: 13
Views: 1922

Re: About the Drake Equation...

Meh, the drake equation isn't really science, since it doesn't make any predictions ("somewhere between 0 and 1 trillion" is not a prediction :P). That's why people make fun of it, especially when it's held up by any news medium as some sort of key concept of cosmology (which is surprisin...
by alterant
Sat Apr 12, 2008 3:30 am UTC
Forum: Science
Topic: About the Drake Equation...
Replies: 13
Views: 1922

Re: About the Drake Equation...

I've wanted to ask since I saw that comic what's so silly or bad about the Drake equation. Of course it's just a long chain of guesses, but so what? Back-of-the-envelope calculations are the bread and butter of science. I read one criticism that said that it wasn't science because it wasn't falsifia...
by alterant
Fri Apr 11, 2008 10:11 pm UTC
Forum: Science
Topic: Physics Lectures (by Walter Lewin)
Replies: 18
Views: 2818

Re: Physics Lectures (by Walter Lewin)

I've been watching the E&M course in parallel with my University of Alberta course for this entire semester. It is superb, particularly the demos. Check out the Kelvin Water Dropper in particular, I thought that one was fantastic. Non-conservative fields as well. There is also a Richard Muller a...
by alterant
Sun Apr 06, 2008 12:35 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2927
Views: 693445

Re: Common Questions

One thing I've wondered for a long time about vision: I notice that, especially in the dark, what I'm seeing is, for lack of a better word, pixelated. I see tiny, tiny dots flashing on a blackish background. I'd estimate that a 10 degree angle slices through 200-300 of them, although it is very hard...
by alterant
Wed Mar 26, 2008 10:46 pm UTC
Forum: Science
Topic: Quantum Mechanics and Consiousness
Replies: 115
Views: 7725

Re: Quantum Mechanics and Consiousness

I have only a VERY basic understanding of quantum mechanics, but as I understand it the uncertainly principle isn't that we can't observe a given particle's momentum and location simultaneously, but rather that a particle doesn't have a momentum and location at the same time. I believe what is desc...
by alterant
Wed Mar 26, 2008 10:31 pm UTC
Forum: Science
Topic: Question re: wavelngth
Replies: 37
Views: 3035

Re: Question re: wavelngth

Oh yes, I see what you mean about there being no limit on frequency related to the speed of the charge. In that case it boils down to what others have said - that the limit of wavelength is zero (but we can never get to zero itself). Whether there is a more practical limit set by the amount of energ...
by alterant
Wed Mar 26, 2008 10:00 pm UTC
Forum: Science
Topic: Question re: wavelngth
Replies: 37
Views: 3035

Re: Question re: wavelngth

Since light, as far as I know, results from moving charges, shouldn't there be a limit on frequency related to our not being able to move charges faster than c?
by alterant
Mon Mar 17, 2008 8:16 pm UTC
Forum: Science
Topic: An electromagnetism paradox
Replies: 17
Views: 2799

Re: An electromagnetism paradox

Just to take a stab here: Well, the way I see it is that an electromagnet contains current carrying wire. When charges in the wire feel the Lorentz force, they feel a perpendicular force just like usual, but are constrained by the wire, so they can't go in loops as they normally would. This crea...
by alterant
Mon Mar 17, 2008 2:20 am UTC
Forum: Science
Topic: How do I calculate gyroscopic force? assuming it's name.. :(
Replies: 4
Views: 10147

Re: How do I calculate gyroscopic force? assuming it's name.. :(

Ah yes, you're right. The tricky bit in that equation is the angular acceleration, but I believe it can be calculated from the angular velocity at the edge of the disc:
α = -ω2r
by alterant
Sun Mar 16, 2008 5:13 pm UTC
Forum: Science
Topic: How do I calculate gyroscopic force? assuming it's name.. :(
Replies: 4
Views: 10147

Re: How do I calculate gyroscopic force? assuming it's name.. :(

It is indeed angular momentum, usually denoted L and given by: L = Iω where I is the moment of intertia of the object and ω is the angular frequency. Moment of inertia has to be calculated from the geometry of the spinning object. For a thin disc spinning about its central axis, I = mr 2 /2 , so if ...
by alterant
Sat Mar 15, 2008 10:32 pm UTC
Forum: Science
Topic: A balloon problem
Replies: 11
Views: 1496

Re: A balloon problem

Sounds a bit exaggerated, but.... :) The balloon is probably made of an insulator, and managed somehow to get some excess charge stuck on it. Insulators can be indeed *very* hard to discharge. But there is no reason for it to follow people in particular (it might just as well induce charge in a wall...
by alterant
Tue Mar 11, 2008 2:57 am UTC
Forum: Science
Topic: The case for upper case K for Kilo
Replies: 42
Views: 5763

Re: The case for upper case K for Kilo

If you want to talk about inconsistencies in SI, why are we still using manufactured standards instead of physical phenomena to define the kg? As far as I'm given to understand, this is because we would need to specify some large number of molecules of element X as making up a kilogram, and we don'...
by alterant
Sat Mar 08, 2008 8:53 am UTC
Forum: Serious Business
Topic: Ben Stein vs. Darwin: The Movie
Replies: 165
Views: 15400

Re: Ben Stein vs. Darwin: The Movie

Too bad... I do enjoy Ben Stein's deadpan. I guess he will now join Bruce Schneier and wear the dunce cap for a while. I loved the Galileo bit! :) A quote from Richard Dawkins explains pretty well why secular people are getting pissed off about "intelligent design": The Rome-deniers, let's...
by alterant
Sat Mar 08, 2008 4:45 am UTC
Forum: Science
Topic: I need help with a simple circuit problem....
Replies: 8
Views: 1372

Re: I need help with a simple circuit problem....

I agree that that is very well explained and correct, but there is another way that in my opinion is a bit quicker and more intuitive. The first step is to find the overall current (flowing in and out of the battery and through the 2.4 and 3.6 ohm resistors). To do that you reduce the whole damn thi...
by alterant
Sat Mar 08, 2008 4:20 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2927
Views: 693445

Re: Common Questions

This question is directed to anybody here who knows anything about cosmology (I'm interested but rather clueless). Does the fact space itself is expanding outward (as opposed to the visible universe expanding into space) have anything to do with the speed of light? Because I can just picture how the...
by alterant
Fri Mar 07, 2008 6:21 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2927
Views: 693445

Re: Common Questions

Here is one thing I've always been curious about. Please tell me if I'm correct about this. If you're in an airplane and you start jumping up and down, jumping up and hitting the roof, throwing yourself against the sides, etc., you do affect the plane's motion instantaneously, but not over the long ...
by alterant
Fri Feb 29, 2008 2:54 am UTC
Forum: General
Topic: INTRO THREAD THE THIRD
Replies: 10922
Views: 2299330

Re: INTRO THREAD THE THIRD

Hi there :)
My name is Ian.
I'm into physics, math, languages... and generally understanding as much as I can about the world, so when zombie/raptor day comes, I'll be well prepared.
Oh, and I'm an engineering student, from Canada.
Cheers,
-Ian
by alterant
Fri Feb 29, 2008 2:19 am UTC
Forum: Science
Topic: Favorite simple circuits for demo, play, world domination?
Replies: 22
Views: 2561

Re: Favorite simple circuits for demo, play, world domination?

I recently ran across the simple FET electrometer circuit , and building it was the best $3 or so I've ever spent at Radio Shack. Hello there; Well, I'm new to the forum so I had better introduce myself in the introductions thread after this, I suppose. I am a beginner at electronics and I tried bu...

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