Practical Men at Work

Are atoms all neat round shapes, as shown in the classroom diagrams? Physicist Arthur J. Freeman of the Watertown (Mass.) Arsenal thinks not. Last week, at the American Physical Society meeting at Massachusetts Institute of Technology, he presented evidence from recent experiments at Brookhaven National Laboratory, where billions of reactor-bred neutrons were fired at atoms of magnetic iron, nickel and cobalt. According to Dr. Freeman's mathematical analysis, the neutrons bounced off the atoms' electrons in patterns that indicate that the atoms have varying shapes. The nuclei of iron atoms are surrounded by a cloud of electrons in almost the classic shape of a globe. But the electrons of nickel and cobalt atoms form cigar-shaped lobes around the nucleus, so that the whole atom looks like a sphere with blisters. Significance of Dr. Freeman's news is that the shapes formed by the electrons may provide an explanation for magnetism, which seems to be caused by "uncoupled" electrons that travel independently as they whirl around the atom's nucleus. It is now up to the theorists to account for the new shapes that Dr. Freeman has "seen."

Other discoveries reported at the M.I.T. meeting:

P: A step toward economic direct conversion of heat to electricity was announced by a Westinghouse research team. Its basis is the so-called Seebeck effect, discovered in Germany in 1821, which shows that a current flows between two different metals (called a thermocouple) when the metals are held at different temperatures. Since such a system has no moving parts, the thermocouple is theoretically an ideal way to generate electricity. Catch has been that most suitable materials cannot stand the high temperatures needed to generate thermoelectric power on a large scale. By combining indium (a soft, silvery metal used in dental alloys) with arsenic and phosphorus, the Westinghouse researchers developed a new chemical compound that performed thermoelectrically at temperatures between 850DEG F. and 1,500DEG F., achieved an estimated 10% efficiency. Compared to the 40% efficiency of the biggest electric generators now in operation, this is not sensational. But future development may close the gap, make possible efficient direct generation of electricity from a coal fire, nuclear reactor or other heat source.

P: The phenomenon of superconductivity, or the unimpeded flow of electricity through metals cooled to temperatures approaching absolute zero (--459.6DEG F.), was given a new twist by Physicist Bernd Matthias of the Bell Telephone Laboratories. A magnetic field dissipates superconductivity. So for half a century, theorists have assumed that magnetic metals could not be used. But Matthias found that some magnetic metals serve unusually well as superconductors. In fact, by combining magnetic metals with others, he can make alloys that become superconducting at the relatively high temperature of --426DEG F. It is even possible, Physicist Matthias adds, to make superconducting metals that behave like strong magnets at the same time.

P: Temperatures at the earth's core were calculated with more precision than ever before by Dr. Herbert M. Strong of General Electric Research Laboratory. As a "thermometer," Strong used the same G.E. hydraulic press that produced man-made diamonds four years ago. Starting from the assumption that at the earth's center is a solid metal inner core under pressure of 3,000,000 atmospheres surrounded by molten metal. Strong subjected heated iron to the unprecedented experimental pressure of 96,000 atmospheres, found that it had a melting point at this pressure of 3,200DEG F. Assuming that the melting point would continue to rise on the same curve as the pressure rose to 3,000,000 atmospheres, he extrapolated to arrive at the temperature at the edge of the earth's inner solid core: about 4,700DEG F.

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