## Search found 260 matches

Fri Apr 24, 2015 7:17 pm UTC
Forum: Logic Puzzles
Topic: Cheryl's Birthday spinoff
Replies: 9
Views: 3413

### Re: Cheryl's Birthday spinoff

Working through the logic: Yolanda knows the year, but not the date. If the year were 2009, 2012, or 2015, there would only be one date possible, so her first statement would be false. Therefore, the year is 2010, 2011, 2013, or 2014. Danny knows the day of the month, which must be 5, 7, 14, 17, or ...
Wed Feb 29, 2012 10:55 pm UTC
Forum: Science
Topic: Theoretical Cold Cure
Replies: 41
Views: 8326

### Re: Theoretical Cold Cure

The problem of rejection dwarfs the original cold, but--suppose CommanderEspresso's housemate is, in fact, his identical twin. Now, could simple (albeit, potentially massive) cross transfusion cure the cold?
Mon Nov 21, 2011 8:12 pm UTC
Forum: Logic Puzzles
Topic: The Logic of Probability
Replies: 22
Views: 7621

### Re: The Logic of Probability

Spoiler:
Probability of conjuring a toad = 0
Because the other wands produce frogs, you see...
Fri Nov 11, 2011 6:30 pm UTC
Forum: Science
Topic: Moving vs Stationary Collision
Replies: 8
Views: 3614

### Re: Moving vs Stationary Collision

Because we assume that the wall is immovable, but the stationary car isn't? Exactly. Okay... good point - question, why doesn't the moving car hitting the stationary car behave like one of those newton cradles and transfer all its momentum to the other car? (thus car vs car at 20 vs 0 <> car vs car...
Mon Oct 24, 2011 10:12 pm UTC
Forum: Science
Topic: What is hypnosis?
Replies: 4
Views: 2004

### Re: What is hypnosis?

--AFAIK, the physiological basis for hypnosis is still uncertain, though the effects are relatively reproducible. --the tendency of people to 'play along' as part of a performance could mean that more outrageous behaviors can be achieved on stage; but a larger part of the psychology seems to be that...
Tue Sep 20, 2011 8:43 pm UTC
Forum: Science
Topic: CMB photon question
Replies: 17
Views: 2698

### Re: CMB photon question

Argh. Shows what happens when I rely on memory. Obviously, I didn't mean Planck Energy - I was thinking of the minimum energy which can be quantized, and jumped to that term because Planck Length and Planck Time actually function that way for their respective dimensions. My point is that somewhere a...
Tue Sep 20, 2011 6:01 pm UTC
Forum: Science
Topic: CMB photon question
Replies: 17
Views: 2698

### Re: CMB photon question

And the converse question--if a photon is redshifted so far that it falls below Planck energy, does this not mean that it can no longer interact with, well, anything? Is that not, mathematically, an equally valid termination point?
Thu Sep 01, 2011 8:34 pm UTC
Forum: Science
Topic: Question from a theist on universal beginnings and entropy
Replies: 290
Views: 25188

### Re: Question from a theist on universal beginnings and entro

10 miles of separation, without a corresponding minimum of at least 10 light-miles of time separation, is indeed spacelike. Why 10 light miles? For a 10-mile interval in space, 10 light-miles, or about 53.7 microseconds, is the magic number--if the events are separated by a 10 mile distance, and ha...
Fri Aug 26, 2011 3:40 pm UTC
Forum: Science
Topic: Two basic physics questions
Replies: 26
Views: 3369

### Re: Two basic physics questions

1. As a martial artist, I can tell you that spinning punches is purely biomechanics. It's easier to throw a spinning punch than a non-spinning one, especially when the rest of your body is spinning. And the rest of your body should be spinning, so you can get all that extra momentum behind it. Um, ...
Mon Jul 18, 2011 5:42 pm UTC
Forum: Science
Topic: A gravity question
Replies: 12
Views: 2527

### Re: A gravity question

Note that these only work exactly with objects that are spherically symmetrical. Applying this to actual planets may will have some deviation where masses aren't exactly spherically symmetrical in their distribution, or where other nearby massive objects may have a say in the matter. FTFY. Real pla...
Mon Jul 11, 2011 8:08 pm UTC
Forum: Logic Puzzles
Topic: 14 prisons
Replies: 13
Views: 3283

### Re: 14 prisons

First note--be very very careful with wording. The first time I read "For every prison the number of floors is equal to the number of cells on the floor" my thought was that in each prison there would be one cell on the first floor, two cells on the second floor, and so on. (which is an en...
Mon Jul 11, 2011 4:12 pm UTC
Forum: Science
Topic: Losing weight...by breathing?
Replies: 33
Views: 5856

### Re: Losing weight...by breathing?

I am not sure if I should make another topic for this but what about losing weight by peeing, pooping, losing blood, spitting, and throwing up. How much do these things effect[sic] your weight and what is the most weight you can lose when these things happen? They're more effective than breathing, ...
Thu Jul 07, 2011 6:06 pm UTC
Forum: Science
Topic: Would you go blind if you became invisible?
Replies: 65
Views: 22506

### Re: Would you go blind if you became invisible?

I'm paraphrasing it correctly, it appears that capturing the incoming light pattern and retransmitting a copy from your other side is the kind of mechanism we were asked to exclude, regardless of the handwaving basis for it. The point is that it still doesn't matter. Technological or magical, true ...
Wed Jul 06, 2011 7:03 pm UTC
Forum: Science
Topic: Would you go blind if you became invisible?
Replies: 65
Views: 22506

### Re: Would you go blind if you became invisible?

No, it's not technological camo, it's magical camo. And if we're not allowing magic *or* technology, then the question is pointless to begin with, because invisibility is impossible. I thought the OP was asking "what if the widget made you transparent, vs. bending light around you?" And I...
Wed Jul 06, 2011 4:10 pm UTC
Forum: Science
Topic: nature of elementary particles...
Replies: 66
Views: 8119

### Re: nature of elementary particles...

See, the problem with the question is that saying "matter", just raises the question, what is matter made of? And, actually, the answer to that question is 'elementary particles', so we see that it's a circular explanation... What I'm saying is that whoever is asking you about it doesn't k...
Tue Jul 05, 2011 8:52 pm UTC
Forum: Science
Topic: nature of elementary particles...
Replies: 66
Views: 8119

### Re: nature of elementary particles...

That's...a challenging question. I submit that the questioner isn't clear on the definition of "elementary", or they wouldn't be asking. If elementary particles were made of something else, they wouldn't be elementary.

And, welcome aboard! Go forth, and post in the introductions thread.
Tue Jul 05, 2011 8:34 pm UTC
Forum: Science
Topic: Would you go blind if you became invisible?
Replies: 65
Views: 22506

### Re: Would you go blind if you became invisible?

I assumed he meant light wouldn't be able to refract through the cornea if you were truly invisible - that would severely interfere with the ability of light focusing on the retina. Now, that's a worthwhile argument; the lens provides much of the refraction needed for focusing, and more is provided...
Tue Jul 05, 2011 4:35 pm UTC
Forum: Science
Topic: Would you go blind if you became invisible?
Replies: 65
Views: 22506

### Re: Would you go blind if you became invisible?

There's another problem with the original statement: Every time Frodo or Bilbo went invisible with the ring they should have also gone BLIND. Your eyes cannot function unless light is reflected off the cornea . If light passes through it (as must be the case with invisibility) sight is no longer pos...
Thu Jun 30, 2011 3:43 pm UTC
Forum: Logic Puzzles
Topic: Unfair auction
Replies: 55
Views: 11547

### Re: Unfair auction

THe winner will always have bid 1 more then the opponent and will win one more token, therefore a-b always stays the same. So you need ad least 103, but 103 wins automatically. Maybe I don't understand what you're saying, but: Suppose A bids 20, B passes. The winner (A) has not bid 1 more than the ...
Wed Jun 29, 2011 8:40 pm UTC
Forum: Science
Topic: Why do we measure half-life instead of just life?
Replies: 62
Views: 14142

### Re: Why do we measure half-life instead of just life?

Also, then, why is half life so useful? Wouldn't 1/4 life be even more stable and accurate than half-life? And 1/8 more still? Or, er, 3/4 and 7/8ths, if I'm thinking backwards. When 1/4 is gone would be more accurate than when 1/2 is gone, is my point. And if you say "the increase in accuracy...
Mon Jun 20, 2011 4:17 am UTC
Forum: Science
Replies: 30
Views: 5703

### Re: Does entropy contradict Evolution?

Another anecdote--I know a creationist Sunday school teacher, who asked me about the same argument. He had simply not heard the caveat that the laws of thermodynamics apply to closed systems, and once I explained that detail, he realized on his own that there's no reason to expect thermodynamic expl...
Mon Jun 13, 2011 4:10 pm UTC
Forum: Science
Topic: Could time be measured in meters?
Replies: 83
Views: 11535

### Re: Could time be measured in meters?

Usually when time is given as distance, it's assumed you're going the speed limit (or a little above) For example Phoenix is 120 twenty miles from Ajo and on average speed limit is around 60 miles per hour. So it's common to say Phoenix is two hours from Ajo. But this is just a short hand for 2 hou...
Thu May 26, 2011 4:15 pm UTC
Forum: Science
Topic: Could time be measured in meters?
Replies: 83
Views: 11535

### Re: Could time be measured in meters?

If you want the conversion for measuring everyday things, a nanosecond is 29.9792458 cm long.
Wed May 25, 2011 5:01 pm UTC
Forum: Science
Topic: Dolphin in a hamster ball
Replies: 25
Views: 3276

### Re: Dolphin in a hamster ball

There are two ways that I think could work. It depends on the friction of the water relative to the surface of the ball, I think. It's possible that the dolphin may be able to move the ball simply by putting its nose against the edge of the ball and swimming forward. And why would the force on the ...
Tue May 03, 2011 7:24 pm UTC
Forum: Science
Topic: I'm doing science, and I need test subjects.
Replies: 79
Views: 10830

### Re: I'm doing science, and I need test subjects.

Screw fruit guys, any part of a plant is a vegetable, including the fruit. Am I the only one who said carrot? I didn't put together the username thing at all. You're not the only one. Carrot was the first thing I thought of, making me wonder what hypothesis we could possibly be testing. [/q...
Mon Apr 25, 2011 7:30 pm UTC
Forum: Science
Topic: Why do you love science?
Replies: 38
Views: 8696

### Re: Why do you love science?

Proper application of science allows us, slowly and haltingly, to become slightly less wrong about how the natural world works. In other words, science imposes an evolutionary selection pressure on memes. (Well, some of them--those related to describing the natural world.) To adapt Churchill: Scienc...
Mon Apr 18, 2011 8:52 pm UTC
Forum: Science
Topic: Dyson Sphere / Ringworld (in)stability
Replies: 36
Views: 7967

### Re: Dyson Sphere / Ringworld (in)stability

I have no physics background, but wouldn't the doppler effect result in a dampening affect on the solar sales? the energy transpher from the light on the sales would be red-shifted on the side that began moving in towards the star, while the otherside would be blueshifted. Except for two things--1)...
Mon Apr 18, 2011 4:03 pm UTC
Forum: Logic Puzzles
Replies: 217
Views: 66212

### Re: The surprise exam paradox

Say the professor tells the student (note: there may as well be only one student) "There will be an exam tomorrow", and "You don't know what day the exam will be". Can those both be true? Certainly: if, for example, either the student is somewhat non-rational, or if the student ...
Mon Apr 11, 2011 8:57 pm UTC
Forum: Logic Puzzles
Topic: A twist on the switch problem
Replies: 57
Views: 10750

### Re: A twist on the switch problem

Yakk, I want to pull that last statement out of your spoiler for discussion: The real catch here is that the other prisoners need to be able to justify that they have found every prisoner, and the warden is just as smart as the prisoners. Is that true? From the problem statement, At any time, any pr...
Thu Apr 07, 2011 8:23 pm UTC
Forum: Logic Puzzles
Topic: Troll math: x^x^x^...=2=4
Replies: 10
Views: 4522

### Re: Troll math: x^x^x^...=2=4

Hmm. Mathematically, the first error is your unstated assumption, "there exist real solutions to this algebraic equation"... But let's see what an answer looks like. I remember from high school algebra that (x^a)^b = x^(a*b) = (x^b)^a; so your initial problem is: 2 ...
Wed Apr 06, 2011 6:35 pm UTC
Forum: Logic Puzzles
Topic: A twist on the switch problem
Replies: 57
Views: 10750

### Re: A twist on the switch problem

The malicious warden would most easily break redrogue's scheme by sending in each prisoner twice in a row.

I've been considering whether we can substitute 'same' and 'different' positions for 'on' and 'off' and it's not enough.
Mon Apr 04, 2011 8:11 pm UTC
Forum: Logic Puzzles
Topic: Partitioning A Formula
Replies: 10
Views: 2687

### Re: Partitioning A Formula

Here's a scheme with n=6 & k=6 where any two sons can die: {1,2,3} {3,4,5} {3,5,6} {1,4,6} {1,2,5} {2,4,6} And, for anyone interested, I constructed it by labeling each son with a 6 digit binary value, with the constraints that each digit should be 1 in exactly three of the six values, but no va...
Mon Mar 28, 2011 6:09 pm UTC
Forum: Fictional Science
Topic: Gravity production on spaceships
Replies: 47
Views: 22898

### Re: Gravity production on spaceships

But then wouldn't the magnetic-ness (can't remember the word) of the clothe have to vary, increasing from the shoes up, so that everything is uniform (you had to pick that word, didn't you)? And then you're stuck being top-heavy when you lie down. For charges, you get a lovely uniform (there's that...
Mon Mar 28, 2011 5:17 pm UTC
Forum: Logic Puzzles
Topic: My write-up of the "Blue Eyes" solution (SPOILER A
Replies: 1368
Views: 421290

### Re: My write-up of the "Blue Eyes" solution (SPOILER A

You could turn it into something relevant by introducing the possibility that you are a ghost, and that you don't know whether you are or not but anyone who sees you will know. If there are ghosts on the beach, then the non ghosts should run screaming in the middle of the night, but only if they kn...
Fri Sep 24, 2010 8:15 pm UTC
Forum: Science
Topic: Humans 2.0
Replies: 143
Views: 10607

### Re: Humans 2.0

5) Minor bugfixes. E.g. appendix, retinal nerve, wisdom teeth, bellybutton, male nipples. Or, alternately, find a use for the useless parts. Rather than remove male nipples, add male lactation.... 7) Aesthetic options. More color choices for everything. Oooh, chromatophores, please. Better skin bot...
Mon Sep 20, 2010 10:31 pm UTC
Forum: Logic Puzzles
Topic: Angels and Demons
Replies: 55
Views: 14581

### Re: Angels and Demons

LOL... all you need is one question to determine who the demon is. Ask both of them if they accept Jesus Christ as their personal savior, assuming Christianity is the default religion in question. Demons deny Christ, and even if he is a liar he cannot answer yes. Angels on the other hand rejoiced a...
Thu Jul 22, 2010 2:23 am UTC
Forum: Science
Topic: Broken reusable supersaturated exothermic hand warmer?
Replies: 11
Views: 9945

### Re: Broken reusable supersaturated exothermic hand warmer?

Thanks for the quick replies. I guess it's possible there were a few crystals left. The packet says to rolling boil for 7-10 minutes and I boiled it for 10, but maybe I need to do it for 15 instead and pay more attention. Even a tiny crystal will do it, so look carefully when you think you're done....
Wed Jul 21, 2010 4:51 pm UTC
Forum: Science
Topic: Irresponsible and dangerous: need help to set knives on fire
Replies: 25
Views: 2726

### Re: Irresponsible and dangerous: need help to set knives on

I'm curious if making a knife blade out of magnesium would work. I know it'd burn nicely, but I'm not sure how easy it would be to get it to look like a knife/get an edge on it before you decide to light it on fire. Solid magnesium is hard to ignite; shavings or powder are hard to put out. My sugge...
Wed Jul 21, 2010 4:03 pm UTC
Forum: Science
Topic: Earth's Centrifugal Force vs. Gravity
Replies: 13
Views: 5451

### Re: Earth's Centrifugal Force vs. Gravity

What's the formula you'd have to use to determine the gravitational flux from the force at the equator? Since it's roughly ~1000mph, what speed would you have to start spinning Earth at to get say half-gravity effect or no gravity effect? And lastly... isn't it centripetal force? Or did centrifugal...
Thu Jul 01, 2010 5:59 pm UTC
Forum: Science
Topic: Calorific value of the typical person
Replies: 21
Views: 4567

### Re: Calorific value of the typical person

Let's see--for men, I'd estimate 42% muscle and 15% fat, so nutritionally that's (.42*4 + .15*9 = 3.03 calories/g); for women let's estimate 36% muscle, 20% fat, so (.36*4+.2*9=3.24); in other words, around 3000-3250 cal/kg. Higher if the cadaver is more obese. That may also neglect the organ meats,...