Search found 89 matches

by opsomath
Thu May 12, 2011 6:59 pm UTC
Forum: Science
Topic: Colorful Metal Salts: What Concentration?
Replies: 4
Views: 997

Re: Colorful Metal Salts: What Concentration?

Meh. Just a couple drops of household ammonia into cupric sulfate (available at the hardware store) should be enough for a good color, and that is a concentration something like that of Windex. No danger.
by opsomath
Thu May 12, 2011 6:57 pm UTC
Forum: Science
Topic: Macromolecular crowding experiments.
Replies: 2
Views: 1461

Re: Macromolecular crowding experiments.

Cool. What will you use, PEG?
by opsomath
Tue Apr 26, 2011 12:47 pm UTC
Forum: Science
Topic: I need a computational chemistry paper.
Replies: 6
Views: 964

Re: I need a computational chemistry paper.

Yes. We tried at the universities at which we both work, but we do not have it. We were hoping someone on here would have access to a better library.
by opsomath
Fri Apr 22, 2011 3:52 pm UTC
Forum: Science
Topic: Favorite home experiments
Replies: 590
Views: 463694

Re: Favorite home experiments

When I took AP Chemistry in high school, I did a demo for the regular chem class of the decomp. of hydrogen peroxide using manganese dioxide (basically the same reaction as permanganate). I practiced it using the 3% stuff, which makes nice bubbles that will reignite a glowing splint. However, for th...
by opsomath
Fri Apr 22, 2011 2:06 pm UTC
Forum: Books
Topic: Farseer and Tawny Man Trilogies
Replies: 12
Views: 7209

Re: Farseer and Tawny Man Trilogies

First, the Farseer/Tawny Man series is unquestionably one of my favorite series, not only in fantasy, but in literature. The entire cast of characters are beautifully done and have larger-than-life moments (such as Burrich and Verity) but at the same time are vulnerable humans who react as real peop...
by opsomath
Fri Apr 22, 2011 1:53 pm UTC
Forum: Science
Topic: I need a computational chemistry paper.
Replies: 6
Views: 964

I need a computational chemistry paper.

Hi Scientists. One of my co-workers needs a copy of the following paper: "On the Use of the Cluster Expansion and the Technique of Diagrams in Calculations of Correlation Effects in Atoms and Molecules" by J. Čížek It's from the Wiley series Advances in Chemical Physics: Correlation Effect...
by opsomath
Fri Apr 22, 2011 1:37 pm UTC
Forum: Science
Topic: Common protein with isoelectric point > 7.6
Replies: 2
Views: 827

Re: Common protein with isoelectric point > 7.6

That could actually work. Thanks for the suggestion.
by opsomath
Thu Apr 21, 2011 2:23 pm UTC
Forum: Science
Topic: Common protein with isoelectric point > 7.6
Replies: 2
Views: 827

Common protein with isoelectric point > 7.6

Is there a biochemist in the house? I am looking for a common protein - one that might be in the stocks of a normal biology or biochemistry lab - which has pI of 7.6 or greater. I would prefer it to be cheap and to have no unusual reactivity or instability. I could prepare cBSA, but I am being lazy....
by opsomath
Fri Sep 24, 2010 7:01 pm UTC
Forum: Science
Topic: Chemistry-related careers?
Replies: 4
Views: 1366

Re: Chemistry-related careers?

Hi MC, I'm a chemistry grad student getting my PhD in December and looking for jobs as we speak. When I figure out the answer to your question for sure, I'll definitely let you know. :) In all honesty, if you want to have a really "scientific" career, you will almost certainly have to go t...
by opsomath
Mon Apr 12, 2010 1:18 am UTC
Forum: Science
Topic: i'm missing something...
Replies: 12
Views: 1654

Re: i'm missing something...

Oh me yarm! Someone told me that the ENTIRE ATMOSPHERE is _directly_ exposed to the vacuum of space! We're all gonna die!
by opsomath
Wed Apr 07, 2010 3:27 pm UTC
Forum: Science
Topic: Looking for some reactants (things that go boom... ish)
Replies: 23
Views: 2948

Re: Looking for some reactants (things that go boom... ish)

That reminds me...the sulfuric acid/sodium bicarbonate mix has been used as a propellant before, eg. in old-timey fire extinguishers.

http://en.wikipedia.org/wiki/Fire_extinguisher
by opsomath
Thu Apr 01, 2010 11:05 pm UTC
Forum: Science
Topic: Looking for some reactants (things that go boom... ish)
Replies: 23
Views: 2948

Re: Looking for some reactants (things that go boom... ish)

The trouble is, everything I can think of that would produce a lot of pressure fast is as dangerous as an explosion. Examples: hydrochloric acid (muriatic acid) and aluminum foil, lye solution (NaOH) and aluminum foil, the aforementioned hydrogen peroxide/catalyst mix. The first two make hydrogen ga...
by opsomath
Fri Jan 08, 2010 1:23 am UTC
Forum: News & Articles
Topic: Atomic-bond resolution microscopy
Replies: 41
Views: 4995

Re: Atomic-bond resolution microscopy

So I'm a chemistry grad student. I run our group's scanning probe microscope, which is what this technique basically is. And compared to this, my stuff is...the Wright Brothers' glider-with-motor compared to the Concorde. Brilliant work.
by opsomath
Sat Jan 02, 2010 1:10 am UTC
Forum: Science
Topic: Spring American Chemical Society Meeting
Replies: 3
Views: 671

Re: Spring American Chemical Society Meeting

My PhD advisor is presenting a paper we did together there, but I am not presently planning on going. Maybe I can talk him into it though....What's your field?
by opsomath
Wed Dec 02, 2009 5:26 pm UTC
Forum: Science
Topic: Why Learn Chemistry?
Replies: 31
Views: 3820

Re: Why Learn Chemistry?

Because chemists get to play with sodium metal.

http://depletedcranium.com/sodiumdrop.jpg
by opsomath
Fri Sep 25, 2009 1:50 pm UTC
Forum: Science
Topic: Diluting 18M Sulfuric acid to 6M in a volumetric flask?
Replies: 23
Views: 5919

Re: Diluting 18M Sulfuric acid to 6M in a volumetric flask?

Also, does anyone know what the pKa of methanesulfonic acid is? I wonder why it's so caustic. Your wish has been granted! http://www.chem.wisc.edu/areas/reich/pkatable/ pKa = 1.6 according to this. Several orders of magnitude less acidic than sulfuric acid; however, that is still plenty acidic enou...
by opsomath
Thu Sep 24, 2009 4:31 pm UTC
Forum: Science
Topic: Diluting 18M Sulfuric acid to 6M in a volumetric flask?
Replies: 23
Views: 5919

Re: Diluting 18M Sulfuric acid to 6M in a volumetric flask?

With all due respect (no disrespect intended to the OP, who is a student and just following orders) this is a dumb experiment and a bad idea. See, it's like this. Mixing similar amounts of conc. sulfuric acid and water is massively exothermic. Therefore, you should do it slowly, by adding the acid t...
by opsomath
Wed Aug 12, 2009 2:09 pm UTC
Forum: Science
Topic: black powder
Replies: 37
Views: 4296

Re: black powder

Sugar(s) will certainly burn violently when finely powdered and combined with a fine powder of [insert your favorite oxidizer here, nitrate, permanganate, chlorate, etc.] That's the only reason I said that about chlorates. Permanganates have a nasty tendency towards spontaneous ignition, too, espec...
by opsomath
Tue Aug 11, 2009 2:19 pm UTC
Forum: Science
Topic: black powder
Replies: 37
Views: 4296

Re: black powder

DEAR EVERYBODY. Please be VERY careful if you use any chlorates in anything, as has been suggested in this thread. They form very unstable mixtures in the presence of traces of acid, which is present in all sulfur as well as other things.
by opsomath
Tue Aug 11, 2009 2:19 pm UTC
Forum: Science
Topic: iodine + methylene blue
Replies: 2
Views: 1442

Re: iodine + methylene blue

First I would like to say that this is my favorite question I've seen on here so far. Based on my experience with aromatic, ionic species such as methylene blue, (http://en.wikipedia.org/wiki/Methylene_blue) gold colored complexes are due to the formation of some kind of donor-acceptor complex or ot...
by opsomath
Fri Jul 31, 2009 8:13 pm UTC
Forum: Science
Topic: Book Recommendations?
Replies: 20
Views: 2105

Re: Book Recommendations?

Once you can handle matrices, run, do not walk to buy Sakurai's Modern Quantum Mechanics. It is a relatively advanced text, but the maths are essentially "college calculus plus linear algebra." And it is a beautiful, first-principles development of the subject without skipping over importa...
by opsomath
Fri Jul 31, 2009 8:09 pm UTC
Forum: Science
Topic: Why can dissolving salt in water be exothermic/endothermic?
Replies: 21
Views: 24468

Re: Why can dissolving salt in water be exothermic/endothermic?

The answer: a lot of things. Basically, it's the difference between the stability (total energy) of a unit of the solid (in its crystal lattice) vs. that same unit in dissolved form (with its ions separated and surrounded by water molecules). This is determined by a bunch of factors. For instance, d...
by opsomath
Thu Jul 30, 2009 8:53 pm UTC
Forum: Science
Topic: How do OLEDs work?
Replies: 13
Views: 1578

Re: How do OLEDs work?

I think the OP might be confusing organic semiconductors/conductors with OLEDs? The latter meaning a light-emitting diode made from the former? If I'm right, organic semiconductors roughly speaking work by the overlap of a lot of orbitals. Add enough pi orbitals overlapping (which each hold a pair o...
by opsomath
Tue Jul 01, 2008 2:05 am UTC
Forum: Science
Topic: Could anyone suggest good scientific literature?
Replies: 18
Views: 2411

Re: Could anyone suggest good scientific literature?

The first sections of Science Magazine are actually quite palatable to someone with some basic science , and the pictures? Gorgeous.
by opsomath
Tue Jul 01, 2008 2:03 am UTC
Forum: Science
Topic: Prove chemistry is the same on Mars
Replies: 21
Views: 2955

Re: Prove chemistry is the same on Mars

One word: spectroscopy. The same light source hits Mars as Earth. All the effects of Martian matter interacting with it can be explained in terms of molecules we have chemically characterized here on Earth. Same goes for the rest of the universe; we can see molecules in nebulae thousands of light-ye...
by opsomath
Tue Jun 10, 2008 3:36 pm UTC
Forum: Science
Topic: A question about the consequences of relativity.
Replies: 21
Views: 3715

Re: A question about the consequences of relativity.

[quote="Owehn" 3) I'd guess that the charge of the black hole would manifest itself in a slight bias in the charges of the radiated particles, so that as the hole loses mass it would also lose charge to the rest of the universe.[/quote] Okay. But what particles would be radiated? Gamma ray...
by opsomath
Tue Jun 10, 2008 10:49 am UTC
Forum: Science
Topic: A question about the consequences of relativity.
Replies: 21
Views: 3715

Re: A question about the consequences of relativity.

1. In general relativity, the gravitational field equations include more than just the mass of an object. They include the energy momentum tensor, which is a 4x4 matrix. This matrix has the energy of the object as one of it's components. 2. The Schwarzschild solution only refers to a stationary bla...
by opsomath
Mon Jun 09, 2008 5:32 pm UTC
Forum: Science
Topic: Getting all this annoying animal off these bones....
Replies: 39
Views: 4648

Re: Getting all this annoying animal off these bones....

Sorry, missed the "Chicago" thing. I forget, living in Georgia, that some places aren't infested with virulent flesh-eating insects with a venomous bacteria-laced bite. If you do use lye, be careful; its heat of dissolution can be enough to boil and spatter it. It does not wash off easily ...
by opsomath
Mon Jun 09, 2008 4:39 pm UTC
Forum: Science
Topic: Thermite!!!
Replies: 18
Views: 2856

Re: Thermite!!!

Burning steel wool should work, although if I remember it tends to give you slag which you'd have to grind somehow.
by opsomath
Mon Jun 09, 2008 4:30 pm UTC
Forum: Science
Topic: A question about the consequences of relativity.
Replies: 21
Views: 3715

Re: A question about the consequences of relativity.

Robin S: Yeah, I'm afraid only a "real physicist" is going to be able to answer this one definitively. Is the apparent gravitational mass not affected by the velocity, only the apparent inertial mass? If so, that brings up an interesting point in itself.
by opsomath
Mon Jun 09, 2008 3:44 pm UTC
Forum: Science
Topic: Getting all this annoying animal off these bones....
Replies: 39
Views: 4648

Re: Getting all this annoying animal off these bones....

Fire ants are a great substitute for the beetles. Just put your dead co-worker critter on the hill. Cover it with a trash can or something to keep the large things which will drag it off to eat at their convenience away.
by opsomath
Mon Jun 09, 2008 3:21 pm UTC
Forum: Science
Topic: A question about the consequences of relativity.
Replies: 21
Views: 3715

A question about the consequences of relativity.

So, I understand that under special relativity, the relativistic mass of an object varies proportionally to the Lorentz factor. (inversely to (c^2-v^2)) Furthermore, for a given mass, it is possible to calculate the Schwartzchild radius, ie, if you squish it into a small ball of this radius, you hav...
by opsomath
Thu May 29, 2008 6:31 pm UTC
Forum: Science
Topic: Bohr Model
Replies: 19
Views: 2345

Re: Bohr Model

As I understand it, the Bohr model does not produce the numbers of atoms in shells at all. If you (inadvisably) wish to use it to calculate something for a non-hydrogenlike atom, you just have to assume the electrons don't interact, or vary the charge on the nucleus in an "effective charge"...
by opsomath
Wed May 14, 2008 11:59 am UTC
Forum: Science
Topic: Wittig Reaction
Replies: 6
Views: 3118

Re: Wittig Reaction

Sorry, phrased that badly. I refer to the pi bond in the double bond. In general, reactions that replace a double bond (pi plus sigma) with two single bonds have that as a driving force, so a double bond is weaker than two single bonds. In this case, though, I suspect the carbon-carbon double bond i...
by opsomath
Tue May 13, 2008 1:32 pm UTC
Forum: Science
Topic: Wittig Reaction
Replies: 6
Views: 3118

Re: Wittig Reaction

Sterics have relatively little to do with carbonyl reactions; what matters more is the relative electrophilicity of the carbonyls. Aldehyde tops this list by a lot; I would expect (offhand guess) 90% selectivity for an aldehyde over a ketone in a Wittig. Hydroxide is really not such a bad leaving gr...
by opsomath
Fri May 02, 2008 4:50 pm UTC
Forum: Science
Topic: Optimal Coffee, Pt, II
Replies: 7
Views: 1826

Re: Optimal Coffee, Pt, II

You're ignoring a whole bunch of properties there. I'm afraid there's no way you'll get anything scientifically meaningful out of this. Feel free to suggest more, this is just what I thought of offhand. Certhas: Well, I guess you could start with not letting your level of caffeine drop below a cert...
by opsomath
Fri May 02, 2008 3:03 pm UTC
Forum: Science
Topic: Optimal Coffee, Pt, II
Replies: 7
Views: 1826

Optimal Coffee, Pt, II

So this was inspired by the optimizing the coffee temperature thread below. My question for people who do pharmacokinetics or what have you: Given the properties of coffee: - Contains 80-100 mg caffeine per cup dose - Temporary appetite suppressor, long term appetite enhancer through acidity/blood s...
by opsomath
Thu Mar 27, 2008 5:01 am UTC
Forum: News & Articles
Topic: Scientists Develop 'Thinnest Material Ever,' One Atom Thick
Replies: 37
Views: 6072

Re: Scientists Develop 'Thinnest Material Ever,' One Atom Thick

This is a pretty awesome trick, but considering that graphite is composed of sheets of this stuff more or less stacked on top of each other, (the 100,000 layers mentioned in the article) I am not predicting this stuff will revolutionize anything anytime soon. Buckyballs and nanotubes, on the other h...
by opsomath
Thu Mar 27, 2008 4:53 am UTC
Forum: News & Articles
Topic: Girl dies as parents pray for healing of treatable illness.
Replies: 172
Views: 14063

Re: Girl dies as parents pray for healing of treatable illness.

That's not how it works. If I shoot somebody in the head and fuck the brain hole based on "religious grounds", I'd go to jail. I would also probably be an electric retard Thanks to you, I have now looked up "electric retard" annnnd I really think that might be the most disturbin...
by opsomath
Mon Mar 24, 2008 5:02 pm UTC
Forum: News & Articles
Topic: Hiker never gave up fight, Hilton said
Replies: 3
Views: 1292

Hiker never gave up fight, Hilton said

RIP, Meredith Emerson. I used to train with this girl, and even though this forum is more dedicated to nerd stories (and I love it for it) I felt her courage deserved to be remembered.

http://www.ajc.com/search/content/metro ... nform_artr

Go to advanced search