Because your parents knew the secrets of Shel Silverstein. And if you want to beat them at their own game, you should learn them too.
I don’t miss Abigail, but now I want her butter pecan ice cream cone.
I mean, if she’s not gonna eat it anyway.
You can have a pony when you have saved up enough allowance to
- Buy a pony and saddle
- Pay for riding lessons
And when you have a big enough allowance coming in every month to pay for
- Boarding, feed, and care of your horse
- Vet bills
- Mommy’s vodka
[quote]Oh, I can explain macroecon to you:
It’s bullshit.[/quote]
I always knew Paul Krugman was full of crap 
Ha!
Well, behavioral economics at the least is certainly the softest of the sciences…if not an outright ideology, and lots of us who work with facts and numbers sometimes hear some of those ‘invisible hand’ statements and it’s hard not to laugh out loud until we realize people are being serious.
I’m not sure why there are still people out there who believe that humans consistently make rational economic decisions, despite all evidence to the contrary.
It’s probably partly due to our issues making value judgments when dealing with any variance greater than two orders of magnitude without a lot of training AND constantly being on the ball (most of us can visualize and combine in the hundredths, but when something’s in the thousandths then we’re embarrassingly bad), but there are likely a multitude of factors, and those factors apply to different people in different ways at different times in their life.
Non-behavioral economics (multipliers, that sort of thing) work well enough though. But that always felt the same as inputs into biological systems (like photosynthesis flows) and such, so I’m not sure they should be called economics.
Or maybe behavioral economics should be treated like a religion? 
Yay, for this awesome thread!! So many science questions to ask …
Here is an ELI5 question: What were some of the key practical tools and procedures that pushed chemistry from basic experiments disproving an elemental model to molecular and even atomic analysis?
I mean the steampunkish 18th and 19th century tools, not contemporary stuff.
It seems like one minute observational experiments are starting to happen and are helping experimentally distinguish different substances, like different kinds of gases instead of just an “air” element.
Then suddenly electrons are being exchanged and counted and atoms are being weighed. I’m missing some parts.
Did they measure electricity? Spectrographs?
What changed?
[quote=“ficuswhisperer, post:2, topic:80992, full:true”]Someone, please ELI5: voxels.
I hear about them all the time as a construct for 3D graphics and imaging but I’m not really sure what they are. I found the Wikipedia article to be mind numbing. Are they just essentially like 3D sprites?
[/quote]
Voxel is short for “volumetric pixel”…which doesn’t clarify anything unless you’re familiar with the meanings of “pixel” and “volumetric”.
To properly ELI5 it: a pixel is a square, a voxel is a cube. Same thing, but 3D instead of 2D.
They aren’t just for computer games; voxels are also used in medical scanners such as MRIs.
Treasury/Reserve distinction is true, but I’d still maintain that the Reserve controls the existence of money. Banks don’t literally create electronic US$ at will, they do it in accordance with rules. If they created as much as they wanted whenever they wanted then they wouldn’t have to think of all of these schemes to make billions of dollars, they’d just choose to have billions. I think that’s an important distinction, since the point was that there is a limited total supply of US$ (it’s just that limit is not the number of bills that have come off a printing press, it is a very complicated limit that fluctuates constantly and we’re getting way beyond five-year-olds).
Yeah, it’s pure ideology. We’ve proved it wrong, and they just keep acting like it’s true. Perhaps because people have have studied economics actually do often act the way economics predicts people will act - that is, they are assholes.
I don’t disagree with economics on everything. But I don’t disagree with everything Trump says either.
Everything, and nothing.
That was where it started, believe it or not. At least in the 19th century, with the concepts of cathode rays and radiation.
There are several major methods in the science (and art) of structure elucidation.
- Chemical Tests
- Mass Spectrometry
- X-Ray Crystallography
- Nuclear Magnetic Resonance Spectroscopy (NMR)
- IR and UV/Vis spectroscopy
- Gas Chromatography
None of these in isolation are usually enough to elucidate everything you’ll want to know about a particular compound.
The old way involved igniting, reacting, testing, transforming, and altering the substance to understand it. It was a deductive process. You’d start of with an assumption about where an active site in a molecule was and then deductively build from there. “There can’t be an oxygen, because I didn’t make any carbon dioxide.” It was time consuming and terrible. Still, from this work we learned how to use mathematical facts to our advantage. The concepts of “equivalents” or “moles” helped us to measure the number of atoms moved in a reaction. We continue to use and apply this knowledge.
Things didn’t really change until we better understood the electron and the structure of the atom, which really kicked off with work done by Rutherford.
First, the basics:
Atoms are generally composed of three different building blocks: The proton, a large particle that we call “positively charged.” A neutron, which is about the same size and which is uncharged, and an electron, which is absolutely tiny and negatively charged. When we say something is positively charged, that’s actually a bit of a cop out. That tells you appallingly little. The three things you need to know about charge are:
- Opposite charged particles are attracted to each other.
- Like charged particles repel each other.
- “Positive” and “negative” have many different definitions. The definition I’ll give you to work with is this: If you move a charged particle through a magnetic field, it will “feel” a force on it. A magnetic field is something you can “see” by pouring iron filings near a magnet.
Positive particles feel this force and are pulled in one direction, while negative particles moving the same way through the same field feel this force acting in exactly the opposite direction. Which direction is which is not important for this explanation.
The neutrons are glue, which keep the positive protons from flying apart in the nucleus. They are not important here except that they have weight. The electrons don’t exactly fly around the atom, but for our purposes, we’ll say that they do. I am lying to you about this. But it’s a useful lie.
What makes an atom a particular element is the number of protons it has. Forget the neutrons, forget electrons. Unless you’re studying the phenomenon called “radioactivity,” which is a special case, we think of this number as being stable. This number decides how many electrons you’ll need to add up the charges to make zero, and create a stable “happy” atom. You can take these electrons away, in a process called ionization and make a less stable ion. Because ions are unstable, positive ions will cling to negative ions until all the charges cancel. When you have one or more ions clinging together, whether they’re of the same or different elements, you have a molecule. A substance like this is also called a compound. You can, believe it or not, shoot a beam of electrons at a compound to kick off an electron, and ionize it. The molecule them becomes a molecular ion.
This lies at the heart of the first truly modern tool used by chemists: Mass spectrometry. With this method, you ionize a substance that you think is pure and fire it through a magnetic field. Remember what I said about the difference between positive and negative? Well now the molecular ion is charged, so it’s deflected by the magnetic field and hits different parts of a detector depending on what it is. The distance it travels is dependent on its mass. The bigger the molecular ion, the less effect a magnetic field will have on its path, while smaller ones hit the detector quicker and earlier. This gives you not only the mass of the molecule, which helps you do the math to perform other chemical tests, but the molecular ion is unstable. It wants to fall apart, and so bits and pieces of it will fly off and have different masses. This is called fragmentation Reading the results is a skill and an art, but based on these fragmentation patterns, it’s often possible to figure out exactly how a simple molecule is shaped.
Mass spectrometry is, however, just one method, and it’s not good for everything. It’s mainly useful for figuring out what elements are in a substance and for organic substances containing carbon which break down in certain ways.
X-Ray crystallography is more useful for inorganic and organic substances that form crystals. Crystals are molecules that arrange themselves in regular patterns over and over again, depending on what they’re made of. The basics are as follows: X-Rays are a form of light. It’s not light you can see with your eyes, but it’s high energy, and when it hits a group of crystals the light scatters in a particular pattern that tells us how the atoms are arranged in the crystal, like throwing a ball through a dark hallway, and when it’s deflected, you can assume there’s a pole or pillar in the direction you threw the ball. The angle of deflection tells you a lot about where the pillar or pole was. It gets complicated after this, it involves a notion in advanced algebra called “group theory.” This math is used to figure out how molecules are arranged.
I’m getting somewhat tired, so I’ll save the other techniques for tomorrow.
Even a stopped watch is right twice a day!
This is so totally badass!! I will be reading and rereading this later tonight and tomorrow probably. Bookmarked.
Probably the single most vital tool in chemistry facilitating the progress you’re talking about is, imho, the standardized logbook and printing.
Once people started rigorously recording what they did in enough detail for replication, and started publishing, things really took off.
No expert on anything, but there’s a fun bit of stuff about physiology that changed the way we looked at things thanks to the squid. Vintage science fans will enjoy this one.
Part the First:
Part the Second:
Is there more about figuring out how equivalents were measured and/or deduced in a lab and the processes that inspired deduction of microscopic parts of molecules and atoms?
Speculating about atoms based on thoughtful observation isn’t that surprising. The world is made of fire; no, it’s water, no, it’s elements; no, it’s atoms …
But experimental processes that begin to support a consensus about the first too-small-to-see parts of a molecule or an atom? Harder for this 5yo to follow.
To render that thought into graphic form, the X and Y axis are 2 dimensional and the Z axis extends us into the 3rd dimension:
We didn’t start to see a consensus emerge about this until Einstein and Planck’s work. A lot of people don’t know that Einstein’s work on the theories of relativity were controversial for a long time and that his more immediate contributions to the sciences involved the photoelectric effect (for which he won the Nobel Prize), and for his description of Brownian Motion as a function of atomic kinetics and movement. Here’s a quick video:
Up until this point the atom was a useful abstraction. Something not truly known to be there. The concept of the atom was proposed by Democritus of Ancient Greece. He proposed that if you cut an object in half, and then cut one piece in half, and then cut a subsequent piece in half, and kept going, you’d eventually reach some definitive peice that resisted further division. This was “uncuttable” or atomon. If you parse the Greek word, you’ll see that this is all it means. A tonsilectomy is cutting out of the tonsils. A tracheotomy is a cut in the trachea that facilitates breathing. Atomism is a philosophical idea, one that seems intuitive, and this is why is was so quickly discovered by the Greeks first. Or was it?
Westerners love the Greeks too much. Don’t get me wrong, they happened to be around early on, and captured a lot of the low hanging fruit of advances in civilization. There’s a lot there that the Greeks truly discovered first, but I don’t believe that they were the first to propose or conceive of atomism. This is my personal opinion. It’s such an intuitive idea that I sincerely doubt that other cultures, and possibly hunter-gatherers never thought to think this way. We humans share and divide possessions all the time without need of so much as a number system. We know Indian culture developed the same ideas around the same time. Preliterate cultures could have easily conceived of it for spiritual reasons and simply never written it down.
In any case, regardless of who proposed it, and how many times this idea was discovered, you have to remember just how old this meme is. It’s at least over two thousand five hundred years old. It makes important appearances in world religions like Islam, which subsequently influenced post-medieval scientific and philosophical thinking in Europe. Of course, even old fashioned alchemists learned by trial and error that proportion is important, but whether these proportions corresponded to quantities of atoms wasn’t clear. Consensus or not, the idea had a track record by the time you get two critical figures in the 16th and 17th century.
Amedeo Avogadro was concerned about quantities of gases. He found that if you held everything else constant (temperature and pressure mainly), the volume taken up by the gas was determined by its identity. He proposed that this was because of the way that invisible but distinct bits and pieces made up matter, and took up a definite amount of space. He held that when you combined substances, you were combining quantities of distinct bits and pieces, rather than something more fluid, and used his calculations to make this clear. He still wasn’t advocating for Atomism as a general idea, just pointing out that this seemed to work predictably and that whatever these bits were made of, they seemed to be bits and pieces that you could count.
Around the same time, Dalton was working on his own experiments with gasses and to the best of our knowledge, came up with the idea of the atom as almost a convenient physical concept, no doubt sharing similar experiences to Avogadro. From these ideas he came up with the Law of Multiple proportions, and he supported his hunch with experiments. It’s important to note that even Lavoisier was converging on the same ideas at the same time. My personal opinion is that the apparatus for measuring and working with gasses had finally become refined enough for people to make these discoveries.
These principles discovered by Avogadro, Dalton, and others contributed to a consensus because they worked. People could rely on these calculations to predict reactions, and it’s particulalry useful with gasses, so Atomism became very popular. Once Einstein effectively proved the existence of atoms, then we became hotly concerned with what they contained and how they worked.
In other words, none of this was obvious, until it became obvious, but the seed of the thought was always there in the back of our minds.
I do want to tackle one more thing today: IR and UV-Vis spectroscopy. I’ll save nuclear magnetic resonance for last, because it’s awesome, and I’ll bring it all together with an example of some lab work I did.
Infrared and ultraviolet light are just that: light. Ultraviolet light is higher energy light that what you and I use to see with our eyes, and infrared is lower energy. When white light hits molecules, only a portion of that light comes back to our eyes. If I see something red, it means that all of the blue, orange, violet, and green parts of the white light are being absorbed, and only the red is reflecting. But it’s important to remember that light is a spectrum and is continuous. Where red begins and infrared ends is almost a matter of opinion. It’s a sliding scale. Light of different color is more energetic moving towards purple and less energetic moving towards red. The least energetic form of light is radio waves, and most energetic are called cosmic rays.
Infrared or IR light makes molecules move. It agitates them. Do you remember how I talked about molecules as just being atoms “stuck” together? Any time you try to pull the atoms apart, they want to spring back together. In fact, these bonds behave almost exactly like springs. When infrared light hits these molecules, some of that light is absorbed and turned into motion. This kind of motion:
Because each kind of motion requires a different amount of energy, every molecule absorbs different parts of the IR spectrum and let the rest pass through. We look at what light got absorbed, and then we can know what kind of bonds were involved. Double bonds, for example, are stronger, and need more energy to stretch than single bonds. Some of these absorptions are so characteristic that it’s impossible for even a novice to miss. For example, a carbonyl (a carbon double-bonded to an oxygen) shows up as a sharp, strong spike in almost the same place, no matter what molecule you’re looking at.
UV-Vis spectroscopy also uses light, but in a different way. Infrared light can heat things, which is why CO2 emissions cause global warming. CO2 is prone to absorbing infrared light better than say… oxygen or nitrogen which will absorb heat but not in the same amount. Global warming deniers claim that scientists don’t consider the role of O2 and N2 in global warming, which shows how little they know about the subject, and how little they know about how scientists do science. [Insert joke here about how I don’t go to where they work and show them how to pass laws and take bribes from corporations. (Took me a second to think of a dishonest profession.)]
What UV light does however, is more violent than IR. Remember how I said it has more energy? UV light from the sun has enough energy to ionize substances in your skin and cause chemical reactions. Some of these are beneficial. Your skin has vitamin D precursors that turn into vitamin D when struck by sunlight. Some of these are harmful, which is why people get skin cancer from overexposure to UV light. We can’t talk about UV light, without talking about electrons.
Remember how I said I was lying to you earlier about electrons? I’m going to keep doing that. What you need to know is that electrons move around the nucleus (the center of the atom with all of the protons and neutrons) in various energy levels. The electrons at the outer levels are easiest to pick off and have the lowest energy, and those at the lowest have the highest. When you shine UV light on a molecule, the electrons get excited. They get so excited, in fact, that they jump up to another energy level. Sometimes they get so excited, they leave the atom, ionizing it. However, the electron is only temporarily excited. It doesn’t want to live where it is, it just showed up for a party, and eventually that electron falls back to its ground state. But in order to do this, it has to lose all of the energy it gained, and this energy leaves as light. Often this light is lower energy than the UV light that struck the molecule, and you get visible colors instead. This is how blacklights work, with UV light striking the molecules in fluorescent compounds and the compound returning visible light.
When you use UV-Vis spectroscopy, you get a curve that shows you how much and what parts of the UV spectrum were absorbed by the electron excitation, and because electrons form bonds, it can give you some information about the kinds of bonding in the molecule.
It’s important to note here that none of these methods are really used in isolation, and they all work together to each give a piece of the puzzle, as I’ll show you next time.
@ActionAbe or anyone else in the chemistry field, could you explain the chemical reaction that explains why fluoride strengthens the enamel in your teeth? I know that I learned and understood the chemical equation back in college chem, but I have since forgotten, and I’d love to have it in five-year-old terms so that an anti-fluoride conspiracy theorist (I knew a guy who thought that the government put fluoride in the water to give the population ADHD) could understand it.
Yet more evidence in favor of teaching Dungeons & Dragons in schools.
Also: you’re a bunch of smarties. Good thread!
