Thoughts re. A very short introduction to The Elements (Philip Ball)
What this really means is that the classical elements are familiar representatives of the different physical states that matter can adopt. Earth represents not just soil or rock, but all solids. Water is the archetype of all liquids; air, of all gases and vapours. Fire is a strange one, for it is indeed a unique and striking phenomenon. Fire is actually a dancing plasma of molecules and molecular fragments, excited into a glowing state by heat. It is not a substance as such, but a variable combination of substances in a particular and unusual state caused by a chemical reaction. In experiential terms, fire is a perfect symbol of that other, intangible aspect of reality: light.
The ancients saw things this way too: that elements were types, not to be too closely identified with particular substances. When Plato speaks of water the element, he does not mean the same thing as the water that flows in rivers. River water is a manifestation of elementary water, but so is molten lead. Elementary water is 'that which flows'. Likewise, elementary earth is not just the stuff in the ground, but flesh, wood, metal.
I was first recently made aware of this interpretation before. It really makes the theory much more plausible and makes it more believable that bright people believed this to be true. -
Lavoisier's belief reveals that he still held a somewhat traditional view of elements. They were generally regarded as being rather like colours or spices, having intrinsic properties that remain evident in a mixture. But this is not so. A single element can exhibit very different characteristics depending on what it is combined with. Chlorine is a corrosive, poisonous gas; combined with sodium in table salt, it is completely harmless. Carbon, oxygen, and nitrogen are the stuff of life, but carbon monoxide and cyanide (a combination of carbon and nitrogen) are deadly. This was a hard notion for chemists to accept. Lavoisier himself came under attack for claiming that water was composed of oxygen and hydrogen: for water puts out fires (it is 'the most powerful antiphlogistic we possess', according to one critic), whereas hydrogen is hideously flammable.
An early example of the fallacy of division/composition. -
Thus there is nothing optimal or ideal about living on an oxygen- rich planet; it is simply the way things turned out. Oxygen is, after all, an extremely abundant element: the third most abundant in the universe, and the most abundant (47 per cent of the total) in the Earth's crust. On the other hand, the living world (the biosphere) has contrived to maintain the proportion of oxygen in the atmosphere at more or less the perfect level for aerobic (oxygen-breathing) organisms like us. If there was less than 17 per cent oxygen in the air, we would be asphyxiated. If there was more than 25 per cent, all organic matter would be highly flammable: it would combust at the slightest provocation, and wildfires would be uncontrollable. A concentration of 35 per cent oxygen would have been enough to destroy most life on Earth in global fires in the past. (NASA switched to using normal air rather than pure oxygen in their spacecrafts for this reason, after the tragic and fatal conflagration during the first Apollo tests in 1967.) So the current proportion of 21 per cent achieves a good compromise.
This constancy of the oxygen concentration in air lends support to the hypothesis that the biological and geological systems of the Earth conspire to adjust the atmosphere and environment so that they are well suited to sustain life - the so-called Gaia hypothesis. Oxygen levels have fluctuated since the air became oxygen rich, but not by much. In addition, today's proportion of atmospheric oxygen is large enough to support the formation of the ozone layer in the stratosphere, which protects life from the worst of the sun's harmful ultraviolet rays. Ozone is a UV-absorbing form of pure oxygen in which the atoms are joined not in pairs, as in oxygen gas, but in triplets.
This smells like the 'backwards' thinking that fuels the arguments from design. The reason that the oxygen level is 'just right' for organisms, is that.. they have evolved to fit the current (or recent ancestral) levels of oxygen in the air. Also, the claims sound rather fishy, and i cudn't either confirm or disconfirm when i tried with Wikipedia and Google. -
And the crowning irony is that gold is the most useless of metals, prized like a fashion model for its ability to look beautiful and do nothing. Unlike metals such as iron, copper, magnesium, manganese, and nickel, gold has no natural biological role. It is too soft for making tools; it is inconveniently heavy. And yet people have searched for it tirelessly, they have burrowed and blasted through the earth and sifted through mountains of gravel to claim an estimated 100,000 tonnes in the past five hundred years alone. 'Gold', says Jacob Bronowski, 'is the universal prize in all countries, in all cultures, in all ages.'
That doesn't seem right to me. The symbolism section on Wikipedia seems to be pretty much only about indo-european cultures, and no data about, say, pre-contact African cultures. However, after my quick googling around, i didn't find any more data about this. -
The metals are the most familiar and recognizable of the chemical elements to non-scientists - for everyone senses the uniqueness of stolid iron, soft and ruddy copper, mercury's liquid mirror. And among these ponderous substances no element has more resonance and rich associations than gold. It is an enduring symbol of eminence and purity. The best athletes win gold metals (in a trio of metals that echoes that of the oldest coinage); the best rock bands win golden discs. A band of gold seals the wedding vows, and fifty years later the metal valorizes the most exalted anniversary of married bliss. Associations of gold sell everything from credit cards to coffee. Platinum is rarer and more expensive, and some attempts have been made to give it even grander status than gold. But it will not work, because there are no legends or myths to support it. There can be no other element than gold whose chemical characteristics have been so responsible for lodging it firmly in our cultural traditions.
Yes, they do. I have seen many such examples. The first three that came to mind are: 1) In Crash Bandicoot games, the player is rewarded with a platinum relic which is better than the gold relic (random video of this), 2) In Starcraft 2, the Platinum league is higher (better) than the Gold league, 3) in music sales classification, platinum is better than gold. I'm sure that there are tons of more examples. -
 So how many elements are there? I do not know, and neither does anyone else. Oh, they can tell you how many natural elements there are - how many we can expect to find at large in the universe. That series stops around uranium, element number 92.* But as to how many elements are possible - well, name a number. We have no idea what the limit might be.
* Elements slightly heavier than uranium, produced by radioactive decay (see later), are found in tiny amounts in natural uranium ores. Plutonium (element 94) has also been found in nature, a product of the element-forming processes that happen in dying stars. So it is a tricky matter to put a precise number on the natural elements.
I thought that only atoms up to Uranium were natural, but apparently not. Wikipedia lists 98 elements that are currently known to occur naturally, either on Earth or in some distant star. I had also conflated natural elements with elements that have at least one stable isotope. However, on reflection i see that i was just wrong, since Radon (Rn) occurs naturally but doesn't have a stable isotope. There are a few other natural elements that also lack a stable isotope (as far as we know, anyway). -
Polar ice contains tiny bubbles of trapped ancient air, within which scientists can measure the amounts of minor ('trace') gases such as carbon dioxide and methane. These are greenhouse gases, which warm the planet by absorbing heat radiated from the Earth's surface. The ice cores show that levels of greenhouse gases in the atmosphere, controlled in the past by natural processes such as plant growth on land and in the sea, have risen and fallen in near- perfect synchrony with temperature changes. This provides strong evidence that the greenhouse effect regulates the Earth's climate, and helps us to anticipate the magnitude of the changes we might expect by adding further greenhouse gases to the atmosphere.
No it doesn't. The causal relation cud be some entirely other way. He might be right, but simply reasoning like that is a causal reasoning fallacy. Also, for good fun, here are two funnies:


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 An isotope of the rare element technetium, denoted 99mTc, is widely used to form images of the heart, brain, lungs, spleen, and other organs. Here the 'm' indicates that the isotope, formed by decay of a radioactive molybdenum isotope created by bombardment with neutrons, is 'metastable', meaning only transiently stable. It decays to 'normal' "Tc by emitting two gamma rays, with a half-life of six hours. This is a nuclear process that does not change either the atomic number or the atomic mass of the nucleus - it just sheds some excess energy.
As a compound of 99mTc spreads through the body, the gamma radiation produces an image of where the radioisotope has travelled. Because the two gamma rays are emitted simultaneously and in different directions, their paths can be traced back to locate the emitting atom precisely at the point of crossing. This enables three- dimensional images of organs to be constructed (Fig. 16). Scientists are devising new technetium compounds that remain localized in specific organs. Eventually, the technetium is simply excreted in urine
This is cool. Never heard of metastable isotopes before. - Â