It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
.....the sands of science are continually shifting in less dramatic ways. In the following, we focus on nine recent examples - a tweak of a definition here, a breaking or weakening of a once cast-iron concept there - that together form a snapshot of that process in action....
We like to think of the periodic table of the elements as immutable. It isn't....
Atomic weight expresses the average mass of an element's atoms relative to those of other elements. It is not to be confused with atomic number, the unvarying number of protons found in the nucleus of atoms of a particular element. The atomic weight adds the tally of neutrons to this, and that's where the problems start: elements may come in different forms, isotopes, whose atoms contain different numbers of neutrons.
The problem with this approach, says Tyler Coplen of the US Geological Survey's Reston Stable Isotope Laboratory in Virginia, is that it perpetuates a misconception. "Teachers are teaching their students that atomic weights are fundamental constants of nature," he says. They are not: the ratio of the different isotopes of a particular element depends on the processes that created, transported or aggregated the material of which it forms part.
As water vapour circulates through Earth's atmosphere from the equator to the poles, for example, molecules containing heavier isotopes of hydrogen fall back into the sea earlier. So the average weight of hydrogen atoms tends to be slightly higher in tropical waters than in seas near the poles. For different reasons, the average weight of the carbon atoms in a hydrocarbon called crocetane, seeping through the ocean floor off the coast of Alaska, is 0.01 per cent greater than the periodic table suggests it should be.
In December 2010 IUPAC stripped 10 of the most troublesome elements - including hydrogen, lithium, boron, carbon, sulphur and nitrogen - of their falsely precise atomic weights. Their weights now come as an upper and lower bound taking into account the spread in isotopic ratios in all known terrestrial samples. Hydrogen, for example, is "H [1.00784; 1.00811]"
Vertebrates used to be so simple. They came in five common-sense categories: amphibians, birds, fish, mammals and reptiles. Birds were the winged and feathered ones, reptiles the scaly, cold-blooded ones. And so on. A place for everything and everything in its place.
Cladistics is now the most commonly used method to classify organisms.... Well, it's obvious that a system of classification is needed. That is, we need words like beetle or conifer so that we can talk about many organisms at one time. In fact, the history of formal classification schemes in biology is long, dating from the 1700s, well before Darwin proposed his theory of natural selection. Today, cladistics is the method of choice for classifying life because it recognizes and employs evolutionary theory.
We've built the bomb. We've built the reactors that provide us with vast amounts of low-carbon power. If that seems remarkable, it becomes all the more so when you realise that the whole enterprise of nuclear fission is based on a misunderstanding.
...This much we thought we knew: when a susceptible element undergoes fission, it will split into roughly equal parts, and if it doesn't, it is down to "magic" numbers. These numbers spring from an elaborate, but slightly shaky, construction for understanding atomic nuclei....
Last year, these ideas were put to the test at ISOLDE, a facility for making rare radioactive isotopes at CERN near Geneva, Switzerland, to predict the outcome of fissioning mercury-180. Dividing mercury-180 evenly gives two zirconium-90 nuclei, which just happen to have a magic number of neutrons and an almost magic number of protons. Given all that, says Phil Walker of the University of Surrey in Guildford, UK, to expect exactly that outcome is "a no-brainer".
Sadly, mercury-180 doesn't play by the rules. It divides asymmetrically into the distinctly unmagical nuclei ruthenium-100 and krypton-80 (Physical Review Letters, vol 105, p 252502).
There is a reason why ice floats on water, and it is called the hydrogen bond. Whatever that is.
Nobel laureate Linus Pauling thought he knew. In fact, the International Union of Pure and Applied Chemistry (IUPAC), which concerns itself with such things, still bases its official definition on the one that appears in Pauling's classic 1939 book The Nature of the Chemical Bond.
Ice is less dense than liquid water because, when water molecules are cold and still, weak hydrogen bonds between them keep them consistently at arm's length. In free-flowing water, however, the bonds are continually breaking and reforming, allowing the molecules to jostle closer together.
IUPAC set up a committee to clear up the confusion. Its conclusion, set out in a seven-page draft redefinition published last year, is that the hydrogen bond is a far fuzzier entity than we thought. "It is not an interaction with sharp boundaries," says Gautam Desiraju from the Indian Institute of Science in Bangalore
As Gregor Mendel showed in painstaking experiments on peas in the 19th century, many traits of living things are all or nothing. Seeds are either green or yellow, round or wrinkled, and so on. This led to the idea that an organism's characteristics are determined by discrete "particles" passed from one generation to the next: genes.
These days, then, what a gene is depends on who you ask. Gerstein has suggested it be defined, in simplified terms, as a union of sequences that encodes one or more "functional products". But he readily admits this is a fudge. "What is function?" he asks. "What does it mean?" A gene that is important for survival in one species may have become redundant in a closely related strain, for instance, even though the sequence is identical. Does that make it a gene in one species and not in the other?
Microscopes are good, but not that good. The view through them gets prohibitively fuzzy when you try to look at things smaller than half the wavelength of the light used for imaging; for visible light, that is anything below a few hundred nanometres. Many things we would like to see in intimate detail, such as the processes that sustain life, are at far smaller scales than that.
We used to think of this "diffraction limit" as a fundamental physical barrier, caused by the bending and spreading out of light waves whenever they encounter an obstacle such as the lens of a microscope. Not any more.
That is almost certainly a huge overestimate. It dates from 1982, when Terry Erwin of the Smithsonian Institute in Washington DC took a headcount of beetles - Earth's most richly speciated group of animals - living in the canopy of a single type of tropical tree in Panama. He extrapolated his tally of 1143 species to arrive at a figure of 30 million tropical arthropods worldwide (The Coleopterist's Bulletin, vol 35, p 74). This phylum of invertebrates, which includes insects and spiders, is thought to account for around one-third of Earth's total species. So even if Erwin's number had been right, it should have translated into there being some 100 million species worldwide.
"THERE ARE NO MAGNETIC MONOPOLES". The garish pink capitals in which the lecturer chalked those words up on the blackboard remain etched in my mind, an indelible memory from my first year as an undergraduate physicist. That was 1997. How the world has changed.
But it turns out we can make our own monopoles (New Scientist, 9 May 2009, p 29). If imbued with a quantum-mechanical property known as spin, individual atoms act as tiny bar magnets with north and south poles. Get the atoms' polar axes to align, and the material itself becomes magnetic.
Now here's the trick. At very low temperatures, a class of exotic materials known as spin ices exist in a "frustrated" magnetic state.
Originally posted by BlackPoison94
And another one....textbooks consider current to flow from the positive to the negative terminal, known to be the conventional method. Whereas the truth is, it's from the negative to the positive...and they still don't do anything to change it!
It's infuriating. We're getting taught false things.
is an idea whose origin will never been known but written down as early as the Egyptians and used by the greats to understand the universe and what is around them like Jābir ibn Hayyān, Alkindus, Ibn al-Haytham, even people you would know of like Galileo, Francis Bacon, Rene Descartes and Isaac Newton.
of inquiry must be based on gathering observable, empirical and measurable evidence subject to specific principles of reasoning. The Oxford English Dictionary says that scientific method is: "a method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses."
It is wonderful how, science, can in the presence of new facts be adjusted, rewritten or even change the commonly accepted conclusion others stated as fact and now confirmed wrong with new measurements, observations and other evidence.