The three-dimensional shape of bubbles in foam; an analysis of the role of surface forces in three-dimensional cell shape determination.
The three-dimensional shape of bubbles in foam; an analysis of the role of surface forces in three-dimensional cell shape determination.
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DOI:
10.1002/j.1537-2197.1946.tb10347.x
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发表时间:
1946
影响因子:
3
通讯作者:
E. B. Matzke
中科院分区:
文献类型:
--
作者:
E. B. Matzke
A uniform foam was constructed by placing bubbles made of a special soap solution, one by one, into a cylindrical dish. The volume of each bubble was controlled by setting the plunger of a Yale tuberculin syringe at 1/10 (or 1/20) of a cc., and making a bubble with the enclosed air. In this way a dish was filled with nearly 2000 (or 4000) bubbles, each of the same controlled volume. Then with a dissecting microscope it was possible to single out, by focusing, any bubble in such a mass and record with precision the number and kinds of its faces. The exact three-dimensional shape of bubbles in foam has been for many years a subject of discussion and speculation among mathematical physicists (Plateau, Kelvin), metallurgists, plant and animal histologists, and students of protoplasmic structure. Studied in this way, 400 peripheral (epidermal) bubbles, of which 200 were free and 200 in contact with the walls of the cylinder, averaged 10.99 faces, with a range from 7 to 14. More than half of the faces of the pcripheral bubbles were pentagonal, and 98 per cent were quadrilateral, pentagonal, or hexagonal. No one combination of faces among those found strongly predominated or could be considered "the type." The commonest of the 43 combinations of faces which were found had 11 faces, of which 3 were quadrilateral, 6 pentagonal, and 2 hexagonal; there was normally one hexagonal face above, in addition to 6 lateral contacts and 4 basal ones. This combination occurred 67 times and constituted 17 per cent of the total number studied. Pentagonal dodecahedra occurred 11 times among the 400 peripheral bubbles. Comparisons were made between peripheral bubbles in foam, peripheral compressed lead shot, and cells in tissues. The bubbles were more uniform than the shot or than the cells. The cells showed a much closer resemblance to the peripheral bubbles than to the peripheral shot, suggesting strongly that surface forces, which are of relatively greater importance in the bubbles than in the shot, are also distinctly significant when cell shapes are being determined. The average number of faces, 10.99, agreed with 11-faceted epidermal cells previously reported by Lewis. The average number of contacts of 600 central bubbles was 13.70, the range being from 11 to 17. More than a third (218) of the 600 foam cells had 14 faces, and more than five-sixths had 13, 14, or 15 contacts. More than two-thirds of all the faces were pentagonal, and 99.6 per cent of all the faces were quadrilateral, pentagonal, and hexagonal. The 600 central bubbles tabulated occurred in 36 different combinations of faces. As in the peripheral bubbles, there was no one combination of those occurring that was strongly preponderant and that could be considered as "the type." The most abundant combination was a 13-faceted foam cell with 1 quadrilateral, 10 pentagonal, and 2 hexagonal faces (1-10-2) which occurred 118 times among the 600 bubbles. The second and third most frequent combinations were of bubbles with 14 faces, 1-10-3 and 2-8-4, which were found 73 and 64 times, respectively. The pentagonal dodecahedron, with 12 faces all pentagons, occurred 50 times. These 4 combinations accounted for 305 of the 600 bubbles. When a large number of bubbles, all of equal volume, are placed into a cylindrical dish so that they are free to glide and adjust themselves, they do not assume the form of the orthic or of the minimal tetrakaidecahedra of Lord Kelvin. Instead, they become arranged in a mass of somewhat irregular foam cells, satisfying, in approximation at least, the equilibrium conditions of Plateau. In this system pentagonal faces predominate; consequently the …