MattC

Can someone explain to me the precise mechanism of 1,2 cleavage by periodic acid? I understand that a cyclic periodite ester is formed, but when I count the oxygens, one seems to be missing. HO OH \ / HIO4 \ --C---C-- --------> 2x C=0 / \ H2O, THF / The periodite ester has four oxygens (two double bonded, two single) and one OH group - water must be involved, but I'm not sure how. I am assuming that in an h20 solution the periodite acid goes to IO4-, and that the H+ isn't playing a huge role. I have looked around on the net, but I haven't found anything that answers my curiosity very well - all the sites just gloss over the actual mechanism and say it's complicated.

and just to cover all bases, you should install a full suite of media codecs. I recommend k-lite media pack.

Actually, oil comes mostly from ancient bogs - plants died in a bog, and because of the water they were not oxidized/broken-down. Over time, the bogs filled up with sediment, and the dead plant materials compressed, and later heated, and so on. Do a google for a more complete picture of the process, and for information on other sources (beds of sea plants, for instance; sea animals and land animals only play small roles in this). What I really wanted to point out is that there is a fundamental misunderstanding here of what cloning is and what it's uses are. We can clone animals, but we can also just breed them - the advantage of cloning, one advantage at least, is that we can produce a genetic copy - an animal, plant, person, whatever, that is genetically identical to the subject (which does not, technically speaking, have to be alive - with current techniques this may be necessary, but I strongly suspect this will not be the case for too long - all we will need is a complete picture of the DNA, without any gaps). In the case of oil, or rather petroleum specifically (after all, that olive oil in your kitchen is oil, and it could be used to power a car, if you wanted to build the right type of combustion engine), we are not dealing with an organism with DNA, but rather an organic compound. Petroleum is a string of carbons and hydrogens (with some other things, but for the most part what we want is the hydrogen and carbon bonds, which can be oxidized to produce water, co2, and lots of energy), and it can indeed be manufactured, both from plastics and from scratch. The problem is these processes are relatively difficult and energy-consuming, so while we *could* make our own petroleum, we'd end up spending more energy making it than we'd get out of it, with current techniques. Current techniques ... that's the keyword. In the near future, it will be feasible to utilize solar power, or some other renewable source of energy, to turn carbon dioxide in the air and water into 100% clean fuels. If we manufacture a fuel in this manner, there is no contamination of other chemicals, as there is in petroleum - nitrogen and sulfur, for example, which, when combusted along with petroleum, produce NOx and SOx (nitrogen and sulfure oxides), as well as other undesired chemicals. Your basic question is, as I see it, can we make our own fuel? The answer is yes - in fact, it's already being done, and within your lifetime (I'm going to assume you're fairly young) you may be able to buy a hydrogen fuel cell car, which basically simplifies the whole process by taking out the carbon and using H2 and O2 to form H20 (water) and energy. Even the oil companies are interested in these technologies, because they know that our oil reserves are declining, and that, more importantly, the oil that is easy to extract is declining rapidly, and if they want to stay on top, they have to be on top of the research into alternatives. Not that they won't milk the last couple drops of money out of oil, at the expense, one might argue, of the quality of life for humans on Earth.

I definately agree that suburbs, as they exist today, are far worse than urban areas. They are basically spread out urban areas, only the extra land is not left to the native plants and animals, but rather replaced by lawns and extra roads. However, that's just the way they are - not the way they need to be. I can imagine a suburban Orange County (a good example, I think, of suburbia gone wrong) without the lawns and extra parking lots, and it would be pretty nice. Part of the problem is that everyone wants to have a car, when they don't need one. Change the people, and part of the problem goes away - in most of these communities, both urban and suburban, people live near enough to the necessities that they could do most of their shopping by bicicle (I myself do). Even if most people retained their cars, we would need far fewer lanes, and that could make a huge difference. I personally like the idea of having very spread out communities, but a well-built city certainly has the potentially to, in an ecologically friendly way, maximize human population. Cities with roof-top gardens, subways (which can be used in spread out communities, or suburbs, as well, though not as effectively), and plenty of parks would be a great way for humans to coexist with rather than dominate nature. Cities also make recycling much easier. More importantly, if people continue to live in cities, it may be possible for the human population to stabilize or even grow some without overwhelming the planet - the 6 or so billion people on the planet now simply can't find enough land to spread out, as per my ideal. I think you're right about farming - while it may be worthwhile to consider the effects of having a majority of the population growing their own food, on their own land, this just isn't going to happen until robotics develops to the point where people wouldn't have to do the work themselves. For the most part, large farms will be needed, and the issue of whether or not monocultures are used is a separate one.

You could always heat and compress a heavy gas ... past it's critical temp, it's going to be a gas despite further compression. A light liquid might be less dense, in this case.

There are many people who would argue with you. I myself and not sure exactly how to answer this - the answer depends upon a number of factors. Cities are great for the environment in that they reduce the amount of area people take up, yes. Cities, however, are not the whole picture - have you ever seen food grown in a city? If you have, it wasn't much. Food is produced outside of cities, in agricultural areas. These agricultural areas are very dense monocultures, and this is arguably very bad for the environment - an area that may contain hundreds of thousands, or millions, of plant and insect species is reduced to a few plants and a few thousand insects, if that. That isn't so good for the environment, is it? True, driving around consumes more gas, and pollutes more, if you are driving across a rural area to a friend on the other side of town than it does if you are walking a few streets away to a friend, in a city. On the other hand, those few blocks of city streets have less biodiversity than a few yards of open land, and while suburban areas are hardly open land, that may be beside the point. Or maybe it's not the point. If you are comparing suburban areas to urban areas, and leaving everything else out, I'd have to agree - suburban areas, as they exist in California at least, are terrible for the environment. The grass on people's lawns here in CA is not native - and it requires water imported over huge distances, at great environmental costs, to sustain that perfect green color home-owners love. And of course most of suburban land is cement. That's even worse, perhaps. It just isn't all that accurate to describe urban areas as ideal, in my opinion. An ideal community would be spread out, with various centers of distribution for food and other commodities, but the area inbetween homes would not be road - it would be open space, or non-monoculture farmland, where people produce locally what they consume locally. In the near future (in my lifetime, as a 24 year old) transportaion will have much less negative impact on environments. Combustion cars will become more and more efficient, especially as oil prices rise, until combustion cars are replaced by solar powered cars, or at least electricity-powered cars using clean-generated electricity. At least, that is my hope - who knows what will happen. If this does come to pass, or if the average fat american gets on his bike every now and then, instead of in a car, traveling a few miles more to visit a friend won't be such a terrible thing. And instead of having a huge number of people in a small area, suffering claustrophobia, slowly forgetting what it is like to be alone, or around nature that man does not control utterly (more control = less perspective, I'd say), we could have healthy populations of people living in harmony with the rest of the planet. That's a little lofty, I know, but it's better to dream about something good than attempt to defend something bad (urban areas) by pointing out how much better they can be than something worse (suburban areas). This is all assuming we are talking abour urban areas such as exist today. An urban area in which large portions of human habitats are underground, or at least covered by gardens, are another matter altogether. You can get pretty creative with this sort of concept, too. Ultimately, though, it doesn't matter whether or not we're talking about urban or suburban or rural - it matters how the community is designed, as any population-density level can be either great or terrible for the world at large ... it just depends upon how it is designed. And now for something completely different. Urban areas have the largest population densities. The higher the population density, the higher the incidence and spread of disease. Large cities suffer the worst outbreaks of just about everything (not counting loneliness ... certainly not that). Sorry if this post seems a little scattered - I am drinking some wine, but I couldn't resist responding.

Ah, what was I thinking? You're right, the velocity of C stays the same. I was thinking of the rate at which it moves away from A relative to B, but that doesn't matter. What matters is how fast it appears to be moving, and if you saw it, even though it moved away from B slower than it moved away from A, it also moved to the side, from B's perspective, and thus the apparant velocity would be the same. I was having a brain fart. As for the other part, I think I'm right. The whole Q is irrelevant because of that mess up, but C, being the one moving fast, would travel through time less rapidly - so when C came back from it's year long trip, two years would have passed for A and B. The faster you move, the slower time moves for you, so light can catch up. Anyhow, thanks for pointing on that silly flaw in my question!

Double post. I edited it out.

Hmmm. Thank you both for the responses! I'm trying to work out in my head how the time rates would work out for all of the systems in this example. I have another question, on a similar subject Say you have two objects that are stationary (A and B), but distant. A third object © is moving away from these two objects C is moving straight away from A at a rate of x C is moving away from B, but not straight away, so it's rate, relative to B, is less than it's rate relative to A C is moving fast, so time for C moves noticably slower. C sees time at point A as moving fast. Time at point B is moving fast but not as fast, because the speed of divergence is less. Yet time is moving at the same rates for A and B So if C leaves A for 2 years (and then comes back), in that period 1 year passes for C (and . B sees that C does not return to A for 2 years, yet relative to B, C should perceive that 1.5 years had passed, instead of the 1 year that C actually perceived as passing (because of it's speed relative to A, which is greater than it's speed relative to B). How does this all work out? A and B see things happening on each other without any dilation of time, yet the dilation of time perceived for C would differ.

Shadows have fuzzy edges, don't they? Light bends a little as it goes around edges, so the further from the source (ie if you use it to amplify an imagine ... you want the shadow to be far from the source, for more amplification) the edges would be more blurred. Since humans have so little mass, maybe the bending is minute and not on a scale that would affect most applications of this. Try it out, let us know!

I have a question for all of you physics experts. Imagine for a moment that at the moment of the big bang, two planets, stars, whatever, are propelled in opposite directions. Exactly opposite directions, for the sake of this thought experiment. One is propelled away from the center in the "left" direction at half the speed of light - this seems feasible to me. Half the speed of light should be obtainable, with enough energy. The other is propelled at the same speed in the opposite direction. Now, these speeds are relative to the center of the big bang. Relative to that center, the speed of these planets/stars/whatever is .5c. Forget gravity slowing them down ... pretend they start out a little faster and .5c is the speed after 10 billion years. Imagine there are no other confusing gravitational pulls confounding things. As I understand it, all speed is relative - not only in the sense of einsteinian relativity, but also in the sense of reference points. I am not moving, relative to the computer I am at, but I am moving relative to the sun, or the moon. In this thought experiment, we have two objects traveling away from each other at .5c, so if you set your reference point to one of them, the other is moving away at the speed of light ... or even more, if we change the parameters of the thought experiment somewhat. If you are one of those planets, and you shine a beam of light at the distant and fleeing planet, the beam of light will travel at the speed of light ... relative to the source, AND the other planet, which is traveling in excess of the speed of light. So as I understand it, time would be very warped for the other planet, relative to the planet with the flashlight. It would have to be going ... back in time, right? Otherwise the light beam would not catch up. At the least, if the relative speeds of the planets was at C, the distant planet would have to not move through time for the light to catch up and hit it at the speed of C. I hope there is a simple answer to this. I've pondered this question a number of times, and always put off doing research, or asking my betters, thinking the answer would come to me eventually. It hasn't. So, experts, how does this work? Does time really stop for that second planet? Or for both, for that matter, since light comes from both? Or is it somehow just impossible for any two particles in the universe to diverge at that rate?

As to why some work and others don't, since we're on the subject ... I believe, but am not sure, that this is due to unfilled orbitals in the material. If all of the orbitals are filled, then each orbital has two electrons, and one has an up spin and one has a down spin, no exceptions. So if a material in it's real-world state has unfilled orbitals, then the electrons in those unfilled, singly-occupied orbitals either have a random net orientation, or, as with magnets, are all aligned in a particular direction.

Just to clarify - hardness is a specific property which is indeed measured (at least, in one way) by scratching things. However, this method is not always a good way of testing something. Ice, for example, at normal temperatures (say, in your freezer, or outside when it's very cold, whatever ...) will turn into a liquid under pressure. When you scratch it, you are actually melting it - ice is much harder than your finger nails, but your nails do not turn into liquid until a very high temperature, whereas ice will become water at low temperatures provided there is enough pressure on it. Most of you know this, but for those who don't, this is due to a unique (somewhat unique) property of water - when it is liquid, it is more dense than it is as a solid. Most other materials, under pressure, solidify. Water (ice) will melt under pressure - this is how an ice-skater slides across the ice when skating. The ice melts under the concentrated pressure of the blades of the ice skates. So, to measure the hardness of ice, you have to test it against something else at a temperature at which, under the pressure conditions of the test (whatever they may be - it depends upon how hard the two materials are grated against eachother), the ice will not melt. If it is cold enough, it will not become a liquid at that pressure. Apply enough pressure and ice will become water, at any temperature. That said, I suspect diamond is harder, but I don't really know the hardness of ice offhand. It's pretty hard, though!

Short of doing research and making an electromagnet, it doesn't sound like you should be trying any of this stuff. It's a bit beyond your means, I suspect, and you definately should not do something you do not understand. However, that said, for theoretical purposes, I will clarify what other posters have said. To turn a metal into a magnet, it must be *formed* while under the influence of a magnetic field. Basically, as a liquid metal cools, the direction of the spin of certain electrons in certain positions around the atoms of a material solidify - that is, they become set and do not change. Like spins attract. So normally, as a metal cools, there is a random variation of spins on those electrons around the atoms in the material, and they all cancel each other out. If, however, you cool the metal under the influence of a magnetic field, then the spins of the electrons will all solidify in the same direction, and you will have a permanent magnet. So, to make a magnet, you would melt down a metal that can be made into a magnet, put the liquid into a cast, subject the liquid metal cast to a magnetic field, and let it cool. When it is done, you can turn off the field, and the metal will now have a huge number of electrons all with the same spin direction, resulting in a magnet. You can also rub another magnet, or an electromagnet, down (in the same direction, each time; you do this many times) a needle, or other potentially magnetic material. This will allow the outer atoms on the needle to "reset" the spin on their electrons, somewhat, resulting in a weak magnet. This is the only magnet making process you should try at home, aside from electromagnets.

Alienware does not actually "make" their products (at least, not the desktops or laptops). Desktops, you can obviously build yourself and save a ton of cash - notebooks are a different story, but alienware notebooks are just rebranded notebooks by Clevo and other companies. If you want a very powerful notebook, there are plenty of better alternatives. The gaming laptops alienware makes are sager laptops (clevo is the ODM ... don't worry about what all that means, if it doesn't make sense), so you can buy them from a sager reseller and save money. Go to http://www.discountlaptops.com/ for a notebook that is the same as the high end gaming alienware laptop, at a lower price. The dell xps gen 2 with the geforce 7800 gpu is also a great alternative.

1 calorie will raise the temp of 1 gram of water by 1 degree c. That's how a calorie is defined. It is not true that .5 calories will do nothing. It most certainly will! That energy does not just sit in some limbo state, non-existant until another half calorie comes along - it increases the energy with which the molecules of water bump into each other and vibrate, and the result is, in the case of an addition of .5 calories added to 1 gram of water, an increase in temperature by half a degree celcius.

I don't use this (though I use firefox) and I cannot vouch for it's efficacy, but here is how it should work to increase browsing speed: When you open a page, you probably spend a few seconds at least before moving onto the next page. You may spend many minutes. In this time, the browser begins to download all of the pages to which the page you are on is linked. In other words, if you have four pages of a news article, while you read the first, the second is downloading. It may or may not download entire pages, images, sounds, etc. I don't know. let us know how it works!

Absolutely - you will get wet faster if you move fast (there are exceptions). To understand why, take two extremes: 1) You are standing still. The number of drops hitting you is basically the average number of drops falling through an area equal to your profile (from above, looking down) in a given amount of time. 2) You are running very, very fast. In addition to always having a 'profile' of a certain area, which is hit by the aforementioned number of drops, you are also walking into drops that are already below the level of your head/shoulders. These drops hit your legs, your stomach, even the fronts of your feet (the parts perpendicular to the surface of the ground. This is assuming the rain is falling straight down, which happens sometimes. Other times, the rain is falling at an angle - then there is a certain speed at which you can walk in the same direction as the failling rain drops (say, they are falling down and to the right - you walk to the right) which will minimize these drops that you walk into. You can walk in the opposite direction and have the opposite effect. Ultimately, if you want to minimize the number of rain drops hitting you, stand very, very still ... under a tree.

As a network administrator for the library of a UC, I suspect that the biggest motivation behind not allowing students to install on computers has little to do with worrying about them spending too much time on messengers and a lot to do with not wanting to constantly deal with spyware, bloatware, bugs, viruses, etc.

I agree that, in conceptual terms, .999 repeat is 1. And who can say that .999 repeat exists in anything outside of conceptual terms, anyway? Of course, if such a thing can exist, so too can an infinitely small number that is the difference between 1 and .9999. If infinity can exist, then so too can a difference, that is infinitly small, between .999 repeat and 1. And if there exists such a difference, then we can say that the two are not equal. In one sense, at least. I also think that people who go around calling others idiots, simply because they attempt to understand things in a different (and in this case, unpopular) way, are most often the idiots. But then, I am being a bit abrasive here, too. I suppose I am just trying to say that I took offense to being called an idiot, indirectly, for adding my thoughts to this thread.

Regarding the quirk in the proof x = .99999 10x = 9.9999 The quirk is this: If you define a set number of 9's, it doesn't work. When you say it goes on forever, you side-step this. Use 4 nines, for instance: .9999 9.999 9.999 - .9999 = 8.9991, not 9 to make that work, you have to pretend that x has two different numbers of 9's when you multiply by 10 you add a nine It's all moot, though, because the difference between .999 repeat and 1 is infinitely small, by definition. however, in real terms, there is a difference. It is just so small that it is impossible to measure OR prove mathematically, because we are using a finite type of math to describe an infinite (non-real?) quantity So technically that is not a proof of anything but the limitations in our math system, in my opinion. At the same time, I'd say that .999 repeat is equal to one. It's a moot point to say otherwise. Of course, math is not my specialty. I agree with YT though.

In short - Light always moves at the same speed, relative to everything. If you shine a beam of light onto a train moving away from you, the light HAS to hit the train at the speed C, whether the train is stationary, or moving away very fast. This is not what happens, of course, with a ball, or anything other than light. If you throw a ball at a person running toward you, it will hit them with a velocity that is equal to that of the velocity of the ball after you throw it plus the velocity of the person running toward you. One way to think of how light works is to think that for light to hit at a constant velocity, time must move at different rates. For instance, if light is hitting you at, say, five photons per second, and you start to run away from the source of light, you would think that you would be hit by only 3 or so photons a second, but you are still hit by 5 - yet the same number of photons are being emitted (5 per second). So time has to slow down for you, for light to catch up. I hope that helps a little!

The whole point of having hydrogen in a car is to turn it into electricity to make it run. using electrolysis to produce hydrogen requires electricity. That would sort of be like giving your buddy a huge pile of quarters, then having him give them to another friend, and having that friend give them back to you. Why would you do it? You KNOW you're not going to get every single last quarter back ... why not just take those quarters to the laundry place yourself? Another analogy ... it would be like using a car's combuston engine and gasoline to produce electricity. Then using that electricity to create gasoline. Then using that gasoline to drive your car.

You would have weight, in two senses. Weight is a force. You have mass no matter what (unless your entire body is somehow converted to light). That force is due to your mass being tugged on by the Earth's gravity, and vica-verca. The force pulls you toward the Earth. Just because youa re falling does not mean there is no force on you - it just means there is no normal force acting in the opposite direction on you. The normal force is the force the earth's surface exerts against you as gravity pulls you toward it. Any object at rest has all of the forces acting on it balanced. Since you are not moving (relative to the Earth) when you are standing still, and since you have a weight (a downward force), you must have an upward force. Hence the normal force. So, you still have that force of gravity/weight acting on you in freefall. It's there, of course .. it's just not counter balanced. The scales, however, do not measure weight/force, exactly. They measure relative weight. Or, better put, they measure the force that is actually being put against them. Now, since you are falling and the scale is falling, it will not register your weight (not entirely true - I'll explain why at the end). Both you and the scale fall, so there is no pressure on you that is pushing the scales against the Earth. Now, the exception. There IS a force pushing the scales back against you, even in Freefall. Unless the mass of the scales were so great (so much greater than yours) that air resistence did not play any role, the scales would be buffed by the air more than you, and therefor there would be a force pushing the scales upward, relative to you, and thus you would appear to have a weight while standing on those scales. How much weight would depend upon the mass of the scales, the shape of the scales, the density of air (your altitude, basically), and perhaps a few other little things I'm overlooking. I hope that helps!