## Search found 35 matches

Wed Aug 27, 2014 4:11 am UTC
Forum: Science
Topic: How hard would I punch something to shatter the moon?
Replies: 7
Views: 3549

### Re: How hard would I punch something to shatter the moon?

Shockwaves propagate through a medium. Since there's no air between the Earth and the moon, you'd either have to punch the thing hard enough that it gets launched towards the moon with enough energy to shatter it, or punch the Earth hard enough that it explodes and ruptures the moon. I bet if you h...
Tue Aug 26, 2014 10:00 pm UTC
Forum: Science
Topic: How hard would I punch something to shatter the moon?
Replies: 7
Views: 3549

### How hard would I punch something to shatter the moon?

How hard would I have to punch something for the shock wave to shatter the moon?

I don't think this requires further explanation.
Fri May 16, 2014 3:17 pm UTC
Forum: Science
Topic: What if we buit a planet with a dyson sphere?
Replies: 12
Views: 3229

### Re: What if we buit a planet with a dyson sphere?

But can you manufacture a planet from raw nuclear fusion, in reasonable time, turning space dust into all the elements you need?

Once you can do that, nothing is scarce: if you need uranium, you find any matter and turn it into protons, then into uranium.
Fri May 16, 2014 2:55 pm UTC
Forum: Science
Topic: What if we buit a planet with a dyson sphere?
Replies: 12
Views: 3229

### Re: What if we buit a planet with a dyson sphere?

Once you have a dyson sphere in place, you've got the ability to collect solar ions and energy passively. You don't have to expend energy to go and get this stuff; you have energy on hand to produce the materials for the planet. Plus your analogy is false: we can't reach hand of god into the sun and...
Fri May 16, 2014 2:07 pm UTC
Forum: Science
Topic: What if we buit a planet with a dyson sphere?
Replies: 12
Views: 3229

### What if we buit a planet with a dyson sphere?

The sun is 333,000 times the mass of the Earth. If we surrounded it with a spherical parabolic collector and sterling engine, at 40% efficiency, we would collect 13,000 TRILLION times the energy we consume. Current commercial enterprise uses fusors to manufacture Molybdenum and Cobalt. Ions and elec...
Fri Mar 21, 2014 2:07 pm UTC
Topic: 1341: "Types of Editors"
Replies: 88
Views: 26051

### Re: 1341: "Types of Editors"

WYSIYSB

When You See It You'll Shit Bricks
Mon Mar 10, 2014 5:49 pm UTC
Topic: 1339: "When You Assume"
Replies: 50
Views: 13318

### Re: 1339: "When You Assume"

I really hate that phrase. It is impossible not to assume. When you drive through a green light you assume there won't be anyone driving through red at that moment. When you walk out the door you assume you won't be mugged. When you go to sleep you assume you'll wake up again. You can't do anything...
Tue Dec 11, 2012 1:55 pm UTC
Forum: Science
Topic: Magnets: how do they work?
Replies: 9
Views: 3958

### Re: Magnets: how do they work?

FancyHat wrote:blahblahblah

Probably the best explanation I've ever heard.
Tue Dec 11, 2012 1:53 pm UTC
Forum: Science
Topic: Magnets: how do they work?
Replies: 9
Views: 3958

### Re: Magnets: how do they work?

What? No. Why do you assume electrons are only found at the edge of a metal object? Are you confusing de-localised electrons with the electrons that convey charge in circuits? No, the "Sea of Electrons" things was the explanation given in advanced chemistry. They said that's how metal wor...
Mon Dec 10, 2012 9:12 pm UTC
Forum: Science
Topic: Magnets: how do they work?
Replies: 9
Views: 3958

### Magnets: how do they work?

The physics of metal is all wrong. Iron is the worst offender. Metallic bonds are explained by the "sea of electrons" model. Essentially, metal atoms all group together, sharing their electrons along the outside of the entire mass. This makes purified metals an extremely strong substance: ...
Thu Sep 06, 2012 11:47 pm UTC
Forum: General
Topic: What if: the core of the earth was chocolate milk
Replies: 5
Views: 1858

### What if: the core of the earth was chocolate milk

After an argument about humans breeding with neanderthal, in which I went on a tangent about the sky being blue and the earth being made of chocolate (there were two arguments, unrelated, and someone was mad because explaining one didn't explain the other), I googled for evidence/claims that the ear...
Tue Aug 14, 2012 12:45 pm UTC
Forum: School
Topic: Book of Fail and Win
Replies: 3
Views: 4739

### Re: Book of Fail and Win

When I took algebra in middleschool, the book I was given for the class was very unhelpful because it didnt actually say how to do anything. Also, many of the answers in the back of the book were clearly wrong, so that was of little help. It would have been ok if the teacher explained how to do wha...
Mon Aug 13, 2012 3:26 pm UTC
Forum: School
Topic: Book of Fail and Win
Replies: 3
Views: 4739

### Book of Fail and Win

I don't remember if I mentioned this before. I don't know if I should put this in Mathematics. I've looked around, but nothing McKeague did impresses me much at a glance. I was hoping this would be a favorite author, but oh well. I'll restate my back story for the fifth time: I went to public school...
Mon Aug 13, 2012 3:07 pm UTC
Forum: General
Replies: 10
Views: 4859

Ah, was just curious if there was a known specific reason.

Obv. I know my way here.
Mon Aug 13, 2012 2:57 pm UTC
Forum: General
Replies: 10
Views: 4859

There's no longer an obvious link to the forums on the front page.

Maxwell's Demon has already sorted all the not-stupid people into this part of the Internet and now has to close the gate?
Wed Aug 08, 2012 10:39 pm UTC
Forum: Science
Topic: Glass lifts visibly into the air? Rocket?
Replies: 13
Views: 3752

### Re: Glass lifts visibly into the air? Rocket?

As I understand it, it is the external pressure that raises the cup into the air. If you look at a free body diagram for the bottom of the glass there will be an upwards force from ambient air pressure but no downwards force from pressure since the other side of the bottom of th glass is interfacin...
Wed Aug 08, 2012 10:36 pm UTC
Topic: The towers provided more than just water (SF short story)
Replies: 6
Views: 8960

### Re: The towers provided more than just water

gmalivuk wrote:This is a forum for discussion, not for just posting your stories. That can be done in the "Your Art and Links" forum, which is where I'll move this unless you actually have something science-related to discuss.

Wait what this isn't scifi?
Wed Aug 08, 2012 4:27 pm UTC
Forum: Science
Topic: Glass lifts visibly into the air? Rocket?
Replies: 13
Views: 3752

### Re: Glass lifts visibly into the air? Rocket?

Propelling anything via vacuum would be extremely inefficient. Without magic, you need quite a bit of energy to create a vacuum in the first place. That energy could be much better spent propelling it in more traditional ways, by multiple orders of magnitude. Yes but if you intend to go, say, 300 l...
Wed Aug 08, 2012 4:24 pm UTC
Topic: The towers provided more than just water (SF short story)
Replies: 6
Views: 8960

### The towers provided more than just water (SF short story)

It was Hoagin's idea as well, of course. Certainly taxes could and would be levied in argentrum, the antimony-hardened silver coins common east of the Dailythyc Bay. Still, Hoagin's idea made sense, and provided much better than any metal taxed system could. After all, drought could strike South Ery...
Wed Aug 08, 2012 2:38 pm UTC
Forum: Science
Topic: Glass lifts visibly into the air? Rocket?
Replies: 13
Views: 3752

### Glass lifts visibly into the air? Rocket?

Wait, why would the glass lift? What holds the water up?

Can we build a closed oblong metal tube and use this to propel it? I thought a closed system wouldn't be able to alter its own momentum...
Fri Aug 03, 2012 7:14 pm UTC
Forum: Mathematics
Topic: "Oh no! We forgot how to say... math... stuff!"
Replies: 294
Views: 92970

### Re: "Oh no! We forgot how to say... math... stuff!"

Even your example of memorizing pi suggests your memorization technique only involves six bits of short term memory. Dunno, it's more complicated than that. Training 1234567890 as ABCDESGHNO, then i.e. 14 = AD = Jesus Christ (Anno Domino == In the year of Our Lord) = Walking on water, 77 = GG = Yak...
Fri Aug 03, 2012 6:25 pm UTC
Forum: Mathematics
Topic: Arithmetic: triangles, oblongs, and ... wtf?
Replies: 5
Views: 1952

### Re: Arithmetic: triangles, oblongs, and ... wtf?

Triangular numbers are a common concept. They're a useful term, as they describe the value of the trivial arithmetic series, which shows up a lot. Similarly, there are several 3d analogs, such as the tetrahedral numbers (1, 4, 10, 20, 35, ...) and variants that describe a pyramid with different bas...
Fri Aug 03, 2012 5:19 pm UTC
Forum: Mathematics
Topic: "Oh no! We forgot how to say... math... stuff!"
Replies: 294
Views: 92970

### Re: "Oh no! We forgot how to say... math... stuff!"

The reason for this is that I heard that most people's ability to remember a number drops off after seven digits... something about short-term memory. 3.14158265358979323846264338327 (I did that without looking it up.) ...you were saying? He said most people, not people like me who could memorize 4...
Fri Aug 03, 2012 5:14 pm UTC
Forum: Mathematics
Topic: Arithmetic: triangles, oblongs, and ... wtf?
Replies: 5
Views: 1952

### Arithmetic: triangles, oblongs, and ... wtf?

http://www.themathpage.com/arith/appendix.htm This funky stuff is all new to me. Triangular and oblong numbers? I've been preparing to give myself a ground-up math reboot, since I stopped doing math and got bad at it. Math is actually a strong point for me. I theorized U-substitution in a couple min...
Wed Nov 02, 2011 8:38 pm UTC
Forum: School
Topic: Abacus, Schools, and Petitions
Replies: 8
Views: 5495

### Re: Abacus, Schools, and Petitions

Shanghai, China is interesting. Do they use the Suan Pan? (Similar device) It seems to be in decline ... as of 2004 it was stripped as a requirement for accounting. China is coming to favor the electronic calculator... I am unfamiliar with any arguments that the use of electronic calculators teaches...
Wed Nov 02, 2011 2:50 pm UTC
Forum: School
Topic: Abacus, Schools, and Petitions
Replies: 8
Views: 5495

### Abacus, Schools, and Petitions

Well may as well put this up front. http://wh.gov/b1c Petition to use the Soroban in elementary schools to teach basic Math. It needs 150 signatures to show up at all, and 25000 in a month to get any attention. I assume these are countermeasures to make sure one man can't change the world... well, o...
Tue Sep 06, 2011 1:54 pm UTC
Topic: 0947: “Investing”
Replies: 148
Views: 34908

### Re: 0947: “Investing”

haso18 wrote:(1.02)^10 = 1.21899
Its that simple. 1219 not 1279

But compounded continuously is 1000 * 2.71828183^(0.02 * 10) which is 1,221 ...
Tue Sep 06, 2011 1:50 pm UTC
Topic: 0947: “Investing”
Replies: 148
Views: 34908

### Re: 0947: “Investing”

So? 2% is really crappy investment to have. Better invest in government bonds instead. And it's still 219\$ you wouldn't have made if you just kept it under your pillow case. However, it's so crappy rate of return it doesn't beat inflation... This is pretty much correct. Long-term investing is the b...
Wed Dec 29, 2010 1:58 pm UTC
Forum: Logic Puzzles
Topic: Black to play and kill
Replies: 6
Views: 2118

### Re: Black to play and kill

zed0 wrote:Out of interest was there a rating on the problem?

It's a Kyu-level problem I think... not sure what level though.

Also I think you're right.
Tue Dec 28, 2010 4:38 pm UTC
Forum: Logic Puzzles
Topic: Black to play and kill
Replies: 6
Views: 2118

### Re: Black to play and kill

No other attempts? The tries thusfar were decent, but your reading fell short. FWIW I haven't worked out the answer myself yet, I'll do that later and soon. I think I see a dead shape though... Black F3 and then Black F4 kills White's shape: if white captures the bottom two stones at E2, D2, the...
Mon Dec 27, 2010 8:26 pm UTC
Forum: Logic Puzzles
Topic: Black to play and kill
Replies: 6
Views: 2118

### Re: Black to play and kill

I'm fairly new to Go, but this is my hunch: E2? My initial hunch was F4, but E2 effectively eliminates the chances for white to get two eyes in there. But then again, I'm new to this. Nice try, but... Try D2 as White's follow up. Black has to block at F4, lest White have enough liberties to...
Mon Dec 27, 2010 6:26 pm UTC
Forum: Logic Puzzles
Topic: Black to play and kill
Replies: 6
Views: 2118

### Black to play and kill

Since today's comic was a chess game:

Black to play and kill. Algebraic notation please (X axis A B C D, Y axis 1 2 3 4)
Mon Dec 27, 2010 5:53 pm UTC
Topic: 0839: "Explorers"
Replies: 90
Views: 28238

### Re: 0839: Explorers

Aww, we have a reference to a child's game (Chess) now but nothing about a real game (Go)? Guess Randy will tackle Othello next.

(Now if anyone knows the difference between Othello and Reversi...)
Thu Oct 21, 2010 1:33 pm UTC
Forum: Mathematics
Topic: Math Books
Replies: 379
Views: 282522

### Re: Math Books

This is now the official thread for questions about math books at any level, from high school through advanced college courses. Well then, I guess I'll delete the other thread and put this here. I'm trying to relearn algebra to fix my foundation, because it crumbled and now I can't do calc or stat ...
Wed Oct 20, 2010 2:28 pm UTC