Search found 146 matches

by Rentsy
Wed Nov 25, 2009 7:43 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0667: "SkiFree"
Replies: 160
Views: 48138

Re: "SkiFree" Discussion

Image
by Rentsy
Sat Jul 11, 2009 12:38 am UTC
Forum: Science
Topic: Sugar Assay
Replies: 7
Views: 1321

Re: Sugar Assay

You get the sugar into a solution, and then use an optical device to measure the polarity of the light.

I do not know the details.
by Rentsy
Thu Jun 18, 2009 2:05 am UTC
Forum: Science
Topic: Need help for science zombie film
Replies: 5
Views: 838

Re: Need help for science zombie film

Well, have a coffee mug appear a few inches above their keyboard as they are typing one day.

The discontinuity of reality ought to throw them for a loop.
by Rentsy
Sun May 03, 2009 9:21 pm UTC
Forum: Science
Topic: What happens at around 200°C?
Replies: 26
Views: 3659

Re: What happens at around 200°C?

A vaporizer is a way of inhaling THC-laced water without the carcinogenic smoke.

(Seemed like someone had to say it)
by Rentsy
Sun May 03, 2009 9:12 pm UTC
Forum: Science
Topic: Negative pH
Replies: 20
Views: 2545

Re: Negative pH

What's important to remember is that because it is on a log scale, things get ridiculous pretty fast. A ph of -1 isn't difficult, but a pH of -3 is pretty much impossible.
by Rentsy
Thu Apr 30, 2009 3:14 am UTC
Forum: Mathematics
Topic: Your favourite calculator
Replies: 43
Views: 5726

Re: Your favourite calculator

The TI-84 Plus, Silver Edition is a beautiful calculator. I love how it sits in my hand, how the colors are interesting but not distracting, how the curves feel as I trace my hand around them, the ease with which I slip the cover off, flip it, and then attach it to the back, how you can slide it on-...
by Rentsy
Sun Apr 19, 2009 3:44 am UTC
Forum: Science
Topic: What if the Second Law could be violated?
Replies: 49
Views: 4209

Re: What if the Second Law could be violated?

Energy and Entropy would not observe a local paraconservation law.
by Rentsy
Tue Apr 14, 2009 7:32 am UTC
Forum: Science
Topic: Is this possible: a bird landing in a moving truck?
Replies: 24
Views: 3419

Re: Is this possible: a bird landing in a moving truck?

At first, the pigeon has a speed of 20 m/s, and the truck is moving at 15 m/s, relative to some point on the ground. Thus, the pigeon moves towards the truck at 5 m/s. As the pigeon enters the truck, the truck appears to be moving at 5 m/s away from the pigeon. Remember, the air inside of the truck ...
by Rentsy
Tue Apr 14, 2009 6:59 am UTC
Forum: Science
Topic: One way to avoid being stretched apart by a blackhole...?
Replies: 100
Views: 7260

Re: One way to avoid being stretched apart by a blackhole...?

Now, as has been mentioned before, for a large enough black hole, one may simply rotate it in peace within the event horizon. Perhaps eventually you will be spaghettified, but until then you can draw a really long, spiral path. Also, wearing a life preserver would help you stay in one peace. I'm tal...
by Rentsy
Wed Apr 08, 2009 8:31 pm UTC
Forum: Science
Topic: Probing The Inaccuracies: Space Warfare
Replies: 271
Views: 26337

Re: Probing The Inaccuracies: Space Warfare

I want to point out that higher-energy lasers (Those farther in the UV spectrum) would be cramped by the tendency of high-energy photons to simply pass through their target without hitting it, like a ball rolling across a lawn with a few garden gnomes. A gamma ray is like a marble, wheras IR is like...
by Rentsy
Fri Apr 03, 2009 6:04 am UTC
Forum: Science
Topic: nature's singularity
Replies: 24
Views: 3808

Re: nature's singularity

You are clearly nuts. Evolution is occurring faster than every - because external genetic factors are more and more important. To prove this, think about how many successful people have decided that "kids aren't for them". Their genes are being cut out of the genepool not because of the wo...
by Rentsy
Fri Apr 03, 2009 2:14 am UTC
Forum: Science
Topic: nature's singularity
Replies: 24
Views: 3808

Re: nature's singularity

I would like to respond to the idea that we could make something smarter than a human. [Begin transmission] You would have me believe that an AI that can innovate is somewhere in the pipeline. Really? We don't have that yet. We're not even close. We can make AI dolphins that freak out other dolphins...
by Rentsy
Thu Apr 02, 2009 5:22 am UTC
Forum: Science
Topic: nature's singularity
Replies: 24
Views: 3808

Re: nature's singularity

Yes, productivity is increasing. We can do tasks faster and with less investment of resources. What took expertise and genius to do crudely and at great expense can now be done very quickly by a stupid lab tech. Let's say, 50x better. Here's the problem: take that expert genius, and they don't work ...
by Rentsy
Tue Mar 31, 2009 6:06 am UTC
Forum: Science
Topic: Theories that are right for the wrong reason
Replies: 32
Views: 4474

Re: Theories that are right for the wrong reason

Good example!

I remember a drawing from that period in human history with an illustration of a man catching dew in bottles, hoping to rise with the morning dew.
by Rentsy
Sun Mar 29, 2009 4:22 am UTC
Forum: Science
Topic: Theories that are right for the wrong reason
Replies: 32
Views: 4474

Re: Theories that are right for the wrong reason

Hmm... this all holds the conceit that not only do our existing models make accurate predictions, but that they explain what is "actually" going on.

We're not sure that's true. We're just closer to an approximation of the truth. The truth will never be known.
by Rentsy
Thu Mar 26, 2009 3:33 am UTC
Forum: Science
Topic: Mysterious force on pendulum
Replies: 10
Views: 1272

Re: Mysterious force on pendulum

I think the equation for dampened harmonic motion fits the line [imath](e^{-xk_1})sin(xk_2)[/imath]

Not [imath]sin(xk_1)-(xk_2)[/imath]
by Rentsy
Sun Mar 22, 2009 6:28 pm UTC
Forum: Science
Topic: Infinite number of elements?
Replies: 27
Views: 4910

Re: Infinite number of elements?

No. A Neutron star is not an atom. An atom is a positively charged group of positive and neutral particles, orbited by negatively charged particles. Those negatively charged particles interact with the negatively charged particles of other atoms, in what are commonly termed "chemical reactions&...
by Rentsy
Thu Mar 19, 2009 4:44 am UTC
Forum: Science
Topic: Comical mistakes in your homework.
Replies: 144
Views: 17671

Re: Comical mistakes in your homework.

I calculated that if all the work done by a hammer pulling a nail out went to motion (of the nail) (instead of heat) the nail would travel at something like 5 times the speed of sound.
by Rentsy
Wed Mar 18, 2009 9:26 am UTC
Forum: Science
Topic: Chemistry Demonstrations
Replies: 56
Views: 6330

Re: Chemistry Demonstrations

Dry ice + Magnesium

The magnesium steals the oxygen from the CO2, releasing lots of heat, and hot carbon burns.

Unbelievable, white-hot in the middle of cold.
by Rentsy
Wed Mar 18, 2009 3:40 am UTC
Forum: Science
Topic: Science and Misery
Replies: 57
Views: 5073

Re: Science and Misery

I like being certain... even if I am certain of uncertainty. The fact that this is somewhat non-intuitive, but proven by everything, comforts me with the knowledge that it is true.
by Rentsy
Tue Mar 17, 2009 5:49 am UTC
Forum: Science
Topic: Newest Theroy
Replies: 13
Views: 1235

Re: Newest Theroy

In my religious tradition*, the phrase "You shall not have false images" doesn't just refer to physical idols. It also refers to "mental images", ideas about G-d that are hopelessly out of date. One of the reasons for this is that idols are terrifically easy to make fun of. Psalm...
by Rentsy
Mon Mar 16, 2009 1:50 am UTC
Forum: Science
Topic: electrocuting a plant
Replies: 8
Views: 1777

Re: electrocuting a plant

So, you apply VOLTAGE to a plant. Voltage is electrical potential energy. Then, depending on how much RESISTANCE (Measured in ohms) the plant has (My guess: quite a bit), an amount of current (measured in amps) flows between the negative and positive voltage nodes. Amps = \frac{Voltage}{Ohms} 1. At ...
by Rentsy
Mon Mar 16, 2009 1:36 am UTC
Forum: Science
Topic: new theroy
Replies: 64
Views: 7987

Re: new theroy

One interesting thing... Suppose the ring rotates with an angular velocity about its axis of symmetry. Now let the ring rotate with the same angular velocity about an axis perpendicular to its axis of symmetry. Taking the ratio of the angular momenta of these two situations we find a value of exact...
by Rentsy
Wed Mar 11, 2009 6:35 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0179: "E to the Pi times I"
Replies: 161
Views: 54991

Re: "e to pi times i" Discussion

My i is your -i And everything can work fine! i is a real number, just not part of the set of reals. Saying that i isn't a number is like saying \frac{1}{2} isn't a number. "Ooo, you're using previously defined number (in this case, integers) and moving them around to define a new, richer set o...
by Rentsy
Wed Mar 11, 2009 6:26 am UTC
Forum: Science
Topic: new theroy
Replies: 64
Views: 7987

Re: new theroy

This is why Occam's Razor is important. Scientific models should be as simple as possible. Look, dude, you might be right. That might be the ultimate nature of the universe. Your only problem is "How does this relate to things we can test with experiments." This is a problem many theorists...
by Rentsy
Wed Mar 11, 2009 6:15 am UTC
Forum: Science
Topic: Throwing Ethics out the Window
Replies: 41
Views: 5129

Re: Throwing Ethics out the Window

I always figured the point of ethics was to have principles that guided your actions, especially at times when you are tempted to break them. Like, I can say "Don't murder" all I want, but let's say you do something, and I'm thinking about knives scraping the flesh off of your bones, well,...
by Rentsy
Mon Mar 09, 2009 1:25 am UTC
Forum: Science
Topic: Mass and Energy remain constant in how many dimensions?
Replies: 16
Views: 2262

Re: Mass and Energy remain constant in how many dimensions?

The point of [imath]e = mc^2[/imath] is that there isn't "mass" and there isn't "energy". There is a mass-energy continuum. Things can move along this mass-energy continuum, but they cannot escape it.
by Rentsy
Thu Mar 05, 2009 5:52 am UTC
Forum: Science
Topic: Nonlinear spacetime?
Replies: 14
Views: 1840

Re: Nonlinear spacetime?

I'm telling you it isn't that simple. It isn't just a matter of "stuff gets complicated so we can't keep track of everything AND if we could keep track of everything we would be able to reverse it". Really. There are some things that cannot be reversed in time and still make sense. Benard ...
by Rentsy
Thu Mar 05, 2009 5:27 am UTC
Forum: Science
Topic: Evolution of another intelligent species on Earth?
Replies: 42
Views: 4758

Re: Evolution of another intelligent species on Earth?

I want to point out that the most important thing humans have done is find an effective way of passing on information to the next generation. We have genetic traits, but we also have ideas that compete for "expression" in the next generation. The ability to build on the ideas of the past i...
by Rentsy
Thu Mar 05, 2009 5:16 am UTC
Forum: Science
Topic: Are preservatives bad for you?
Replies: 45
Views: 8187

Re: Are preservatives bad for you?

Botulism is really bad. Preservatives prevent people from getting killed.
by Rentsy
Wed Mar 04, 2009 6:03 am UTC
Forum: Science
Topic: Evolution of another intelligent species on Earth?
Replies: 42
Views: 4758

Re: Evolution of another intelligent species on Earth?

That ignores another, pertinent point regarding non-human evolution in the forseeable future: we're already here. The evolutionary zeitgiest of Earth right now favors animals that can live with us, not replace us. Rats, snakes, and birds, not large, near-intelligent animals.
by Rentsy
Wed Mar 04, 2009 6:00 am UTC
Forum: Science
Topic: Nonlinear spacetime?
Replies: 14
Views: 1840

Re: Nonlinear spacetime?

You can't run an irreversible process in reverse. That's the point. Consider a frictionless pendulum. Entropy is constant. KE gets converted into GPE, back and forth, back and forth. That's a reversible process. The laws of physics work in reverse because entropy, in this system, is constant. If ent...
by Rentsy
Wed Mar 04, 2009 5:38 am UTC
Forum: Science
Topic: Electric Field in a Dipole falls off as r^3?
Replies: 6
Views: 3291

Re: Electric Field in a Dipole falls off as r^3?

A magnetic field also falls off at the cube of the distance. A monopole would fall off the square. The fact that a magnet is basically two monopoles causes them to fall off faster, especially because the farther away you get, the ratio of the distance between the two poles to the distance from one p...
by Rentsy
Wed Mar 04, 2009 5:32 am UTC
Forum: Science
Topic: Infinite Grid of Springs
Replies: 14
Views: 2663

Re: Infinite Grid of Springs

Your tuition can't buy an intuition.

Sorry.
by Rentsy
Wed Mar 04, 2009 5:26 am UTC
Forum: Science
Topic: Evolution of another intelligent species on Earth?
Replies: 42
Views: 4758

Re: Evolution of another intelligent species on Earth?

Stephen Jay Gould contends that life - intelligent life - and humans - are all incredibly unlikely events. Rather than "working towards some goal", evolution just goes with whatever works. It is pure luck that we're even here. Consider the odds of the Dinosaur killing asteroid a) hitting e...
by Rentsy
Mon Mar 02, 2009 5:54 am UTC
Forum: Science
Topic: Nonlinear spacetime?
Replies: 14
Views: 1840

Re: Nonlinear spacetime?

There are two big ideas. The first is that there is no time, there is no space, there is only a continuum of space-time that one moves through. To put it simply, if a person moves through space faster, they necessarily move through time slower, and vice-versa. Now imagine this "fabric" of ...
by Rentsy
Sun Mar 01, 2009 8:06 pm UTC
Forum: Science
Topic: Best way to lower boiling point of water?
Replies: 22
Views: 12688

Re: Best way to lower boiling point of water?

tantalum wrote:Tell us details of your heat pump and why you think a phase-change is an important part of your heat pump.


I second that motion.
by Rentsy
Sun Mar 01, 2009 8:03 pm UTC
Forum: Science
Topic: Trip to the moon [Homework problem]
Replies: 21
Views: 4830

Re: Trip to the moon [Homework problem]

Ah, the fun of assigning physical meaning to the numbers that pop out of equations.
by Rentsy
Sun Mar 01, 2009 6:26 pm UTC
Forum: Mathematics
Topic: Your favorite paradox
Replies: 159
Views: 22357

Re: Your favorite paradox

A paradox is an unintuitive conclusion. I accept that. However, the reason the result is "unintuitive" is, ultimately, because new ways of thinking have not been developed. That's why I don't like calling The-Put-A-Twin-On-A-Spaceship-At-Near-Light-Speed the "Twin Paradox", becau...

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