Wednesday, March 21, 2012

American Atheists’ symbol is scientifically inaccurate and misleading


American Atheists’ symbol is scientifically inaccurate and misleading

American Atheists
“When American Atheists (AA) was founded in 1963, they chose the atomic symbol (as seen in the graphic) as their logo.The use of the atomic symbol flowed from their belief that human progress can best be achieved through the scientific method and rational, open inquiry.
Some of the features of this symbol:
The lower part of the symbol is broken or open ended. This refers to the incompleteness that is inherent in the sciences. As AA’s web site says: “Not all of the answers are in.”
The incomplete vertical electron orbit forms the letter “A” which represents Atheism.
The letter “A” in the center of the symbol does not represent Atheism. It stands for the first letter of the name of the country where an AA affiliate group is located — America in this case.
Unfortunately, many people associate this symbol with danger, nuclear waste, hazardous radiation, nuclear bombs, etc. It has not found general acceptance.”
See: American Atheists http://www.atheists.org/
Both eighth grade science classes and American Atheists use the long outdated – and overly simplified – 1911 Rutherford model of the atom, which represents the standard model of the atom as a mini solar system, even though this conception is considered scientifically inaccurate today. The updated and much more accurate understanding of the atom being that of a fuzzy particle cloud.
“In 1911, Rutherford proposed a revolutionary view of the atom. He suggested that the atom consisted of a small, dense core of positively charged particles in the center (or nucleus) of the atom, surrounded by a swirling ring of electrons. The nucleus was so dense that the alpha particles would bounce off of it, but the electrons were so tiny, and spread out at such great distances, that the alpha particles would pass right through this area of the atom.Rutherford’s atom resembled a tiny solar system with the positively charged nucleus always at the center and the electrons revolving around the nucleus.
The big problem with answering “what does an atom look like” is that in order to look at something, we normally shine light on it and observe the light that bounces off. Visible light has a wavelength that is much bigger than atoms. It is impossible to make out small details of objects by probing them with waves of large size — the waves simply flow around the small object. Shorter-wavelength light may be used, but the energy per photon increases as the wavelength shortens. As it turns out, when the light has a wavelength comparable to the size of the atom or smaller, it has enough energy to change the atom by moving the electrons around. This is one consequence of Heisenberg’s Uncertainty Principle. We cannot say where the electrons are and how fast they are moving at the same time, and hence we cannot draw a picture with a little electron on one place sitting on a circular orbit. The fuzzy picture at the bottom of the page linked to is closer to the truth, describing the probabilities of finding electrons, depending on where you look for them.
The nucleus, containing protons and neutrons, has a similar problem, but it is much much smaller than theelectron cloud, and hence the energy of a photon needed to resolve structure is much higher. Heisenberg’s Uncertainty Principle applies to neutrons and protons as well, and so a fuzzy nucleus isn’t such a bad representation either. But for show in a classroom, the clear pictures showing the details get across the important points that atoms consist of protons, neutrons, and electrons, that the protons and neutrons are in the nucleus and the electrons are found at larger radii.
Question – How is it that as you said in a hydrogen atom the electron exists in a cloud around the nucleus? Isn’t it just one electronWhy is it a “cloud” around the nucleus and not like a planet around a star?
Answer – Yes, it is just one electron. The point, however, is that an electron is not what you think it is.  It really is a smear, not a dot. That smear can, under some conditions, by pulled into a small region or under other conditions expanded out to a large region. So far as we can tell, that’s all there is to it. As for the idea that there’s really a dot-like position hiding in there, as we discuss above, violations of the Bell Inequalities show that such pictures are false.
Question – Where can I find a diagram of an atom and info about molecules for 5th grade level?
Answer – An atom has two main parts: A very tiny nucleus and the electrons that surround it. A very common picture that is often shown looks like the following one:http://upload.wikimedia.org/wikipedia/commons/thumb/e/e1/Stylised_Lithium_Atom.svg/220px-Stylised_Lithium_Atom.svg.png
This is partially true, since it shows that the electrons live around the nucleus, but it is also misleading since it gives you the idea that the electrons move in circular paths. In fact, the electrons do not move in nice orderly circles. An electron should be thought of more as a fuzzy “cloud” that is able to fill the whole space around a nucleus, kind of like this picture:http://upload.wikimedia.org/wikipedia/commons/2/23/Helium_atom_QM.svg
This picture is supposed to give you the impression that the electron is all over the place at the same time. The darkness of the black color indicates that where the electron is most likely to be found at any given instant. As you see, it is most likely to be found close to the nucleus, and not so likely to be found far away. This is still not a very accurate picture, but it’s better than the first one. In actual fact, for example, the nucleus should be drawn much smaller, so small that you would not see it. I’m sure if you look, you can find some other (better) pictures in your school library.”
See also: New and Exciting Physics: What Atoms Look Like: http://van.physics.illinois.edu/qa/subcategory.php?sub=What%20Atoms%20Look%20Like
Particle cloud
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