Class Warfare Blog

July 17, 2012

Some Basic Physics the Science Channel Misses . . . Over and Over and . . .

Filed under: Education,Science — Steve Ruis @ 11:23 am
Tags: , ,

I don’t know about you but I enjoy some of the programming one sees on “the cable” as it were. As a scientist I do tune into science programs and there are some good ones. As an illustrator and scientist, though, I cringe when I see some of the representations pumped into our flat screens.

It may not seem like much to you, but if we aren’t committed to the truth in reality and just start choosing what to believe, as scientists we will be no better than schismatic religionists.

One of my pet peeves is the way these folks display representations of atoms. Since they are too small to see optically (naked eyes, optical microscopes, etc.) the only way we can “see” them is to measure certain parameters about them and have a computer reconstruct the variations in the fields measured. We still don’t get a sharp picture and it is quite probably the case that a sharp picture is impossible. Given that, what does theory say about the appearance of atoms?

Theory says that atoms consist of two parts, a solid bit called the nucleus and a wispy “cloud” that surrounds it. The cloud “looks” much like photos of globular galaxies, that is there is more and more of “it” as you get closer and closer to the center and less and less as you move away. There is no outer skin or boundary. The nucleus is made from protons and neutrons and the cloud of electrons. Since atoms are too small to see, there is no chance of seeing an electron, which still hasn’t yielded up a measured size. All we know now is that electrons are at least 10,000X smaller in largest extent than are protons. The effective difference between protons and neutrons is that protons carry a large amount of positive charge while neutrons have no charge at all (they are “neutral” in charge, hence “neutron”). An Aside Like the Higgs boson, the neutron was predicted before it was discovered—sometimes theory follows data, sometimes it leads.

Not only are electrons small in size they are also small in mass. You would need a pile of almost 2000 electrons to weigh as much as one proton or neutron. Consequently the electron cloud makes up a tiny fraction of 1% of the entire atom’s mass. There you have it. Atoms are made of a dense central core (the nucleus) which contains almost all of the mass and all of the positive charge surrounded by a “cloud” of electrons that possess a tiny, tiny fraction of the nucleus’s mass, but all of its negative charge. The “cloud,” though, takes up a volume (however that may be defined) that is millions of times greater than that of the nucleus. So to build a valid mental image of an atom one would start with a black background and drop a tiny (really tiny) speck of light on it (the nucleus) and surround it with a faint patch of light, so faint as to be almost invisible (the electron “cloud”), a cloud that is brighter closer in and less bright as you look away.

What we get from the Science Channel, et. al. is a bunch of grapes with raisins whizzing around orbiting them and leaving vapor trails behind. This is an image created in the early part of the 20th century and has been proven entirely wrong (no grapes, no raisins, and interestingly no “orbits,” that’s right the electrons do not orbit the nucleus like tiny planets around a tiny sun). They make it even worse by coloring the “protons” and “neutrons” in the nucleus to make them more visible! For one, there is no color at the atomic level, but what is really wrong about this is that there are no protons and neutrons “in” the nucleus. They are gone. One of the biggest problems this theory had to account for was what made positively charged protons and electrically neutral neutrons stick together. Their mutual repulsion or lack of attraction should cause them to fly apart. The solution to this problem came from measurements. The atomic nuclei weigh less than the corresponding numbers of neutrons and protons do! Later it was discovered that atomic nuclei are made in the intense heat and pressure of the interior of stars (in a process called nuclear fusion). At extreme pressures and temperatures protons and neutrons are merged to make new particles, the nuclei, with some of the mass of the protons and neutrons made into energy (eventually to become sunlight). The resulting atomic nuclei, not having enough mass to make the protons and neutrons back, are stuck in their configurations. And since those temperatures and pressures don’t happen too many places atomic nuclei, which are new, single particles—not clumps of particles stuck together (and which is why I said the nuclei were made “from” not “of” protons and neutrons)—continue in that form. Another Aside Ordinary nuclear fusion only has enough temperture and pressure to make the elements up to iron, the heavier elements only get made when starts explode!

Why these people can’t get it right is beyond me.

And for another thing, when they show the planets and the Sun, they place them much too close together . . . but that is another rant.

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