SILVER TREES DAVID I. GLEIM Dickinson College, Carlisle, Pennsylvania T o DEMONSTRATE adisplacement reaction, I know of no and 32 of volume 2 several methods for the production simpler or more spectacular method than the formation of silver trees or "Arbor Dianae." In one procedure, of a silver tree. which he claimed succeeds better than any of the If a loose coil of fine copper wire is inserted into a 500- others, the electrolyte was a mixture of silver and ml. Florence flask containing 10 g. of silver sulfate dis- mercuric nitrates, while the displacing agent, mercury, solved, hy heating, in 480 ml. of distilled water and 20 was introduced in the form of an amalgam with silver. ml. of concentrated sulfuric acid, a silver tree will start I t is interesting to note that almost 150 years ago to form immediately and in from ten to fifteen minutes will occupy a large volume of the flask. This growth is quite fragile and much handling d l cause it to hreak from its wire support. If the finer details of the structure are to be observed one must resort to the microscope. On a clean microscope slide place a drop of concentrated sulfuric acid and dissolve in it, with the aid of a little heat, a very small quantit,y of silver sulfate. Too high a concentration of the silver salt will produce secondary effects. A small piece of a metal below hydrogen in the electromotive series, as antimony, bismuth, or copper, isallowed to fall on the drop, which is then covered with a cover glass. With the exception of bismuth, a growth will form al- chemists were aware of equilibrium in reactions. Accum's proredure was carried out by the writer. most immediately. When bismuth is used as the disThe growths produced remind one of an aerial view placing agent, the sulfuric acid must be diluted with a small drop of water. Silver. nit,rate dissolved in water
Dilute
AsNO, t Bi
of a wooded area, with here and there a taller tree standing out amongst the others. Their height varies from one eighth to one quarter of an inch and they are
Typical Silver Tree in Approrimately Firm Minutea
will give results similar to those with silver sulfate in sulfuric acid. Accum, in his "System of Theoretical and Practical Chemistry," published in 1814, describes on pages 31
Dilute AgNOx i Cu
remarkably sturdy compared to trees formed by ordinary displacements. As a demonstration the procedure has no value.
OFFICIAL BUSINESS 267th MEETING
..
Dishurscment,~: Hostelry. . . . . . . . . . . . . . . . . . . . . . . . . . . $1761.22 Printing, postage, et,e... . . . . . . . . . . . . . 369.41 Dues to NEACT.. . . . . . . . . . . . . . . . . 82.00 Miseella~leous... . . . . . . . . . . . . . . . . . . 93.97 I t e f u n d ~.. . . . . . . . . . . . . . . . . . . . . . . . . . 112.00
The 267th meeting of the NEACT was held on October 18, 1952, a t St. Paul's School, Concord, New Hampshire. The Eastern Association of Physics ~~~~h~~~met simultaneously in a joint meeting, l-he
program consisted two The Total Expenses. . . . . . . . . . . . . . . . . . . . . . . . . $2428.60 first was presented by Kenneth A. Blaine, a leather tanner andchemist at the International Shoe Company, Cash on Hand.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $ 222.90 Manchester, New Hampshire, who outlined the history, president ~ i f f anlloullced ~ ~ d the followillg appointchemistry, and present status of leather tanning in an ments and committees: interesting talk, enlivened with amusing anecdotes. Richard D. Wells, research director of Bates Manu- Assistant Editor of the .Vetus Letter: Eva AZ. Ruggli, 6 i Dana St,!.&, Cambridge 38, Mnsrarhusetts. Company' Le'viston' Ivas the second Assistant Edilor q f the 12eporl: \Villiam G. Chaee, L ~ ~ ~Textile ell speaker, whose topic was "Science education for today." L ~ , Mn8saehuRetts, ~ ~ ~ ~ , His original thinking and able expression won acclaim Rcpresentaliues qf the AIEACY'on t,he S e a . England School Science from thegroup. His address appeared in the February Council: Dorothy I!.' Gifford, Lincoln School, Providence, Rhode Island, ex oficio; Hdcn W. Cranley, 11-alnut Hill issue of THISJOURNAL. School, Natick, Mnssachusrtts; Everett F. Learnsrd, NorAfter an excellent luncheon in the Alumni Hall, the High School, Kora.aod, Massachusetts, afternoon sessiou concluded with a lecture-demonstra- ,yuheornmiitees the NEAW chemical ~ , j ~commitlee: ~ ~ t i ~ ~ tion by Karl Woodcock, head of the Physics Depart(1) To d r a w u l ~a syllabus for nursing sahoal students: Margaret M. Parks, University of Rhode Island, Kingsment of Bates College, Lemiston, Maine. Dr. Woodton, Rhode Ialand, Chairman cock's topic was "Microwaves." He presented analRavmond E. X e d , Simmons College, Boston, Massaogies of microwaves with light, using special equipment chusetts. developed for easy understanding of the underlying Anne R. Kclley, Itoxbury Mcmorial High School principles. (Girls), Boston, Massachusetts. ~ ~~ ~~ president i ~ ~ ~ ~ ~ W, ~ i ~ ~i f ~f~ ~~ ~ (2)d ~~TO t estahlish .h criteria~far judging science fairs: Standish Deake, Milton Academy, Milton, Msssachuronducted the business meeting. The Secretary resetts, Chairman. port,ed t,hat the following new members had been Joseph H. Rohloff, Nelson W. Aldrich High School, Warwick, Rhode Island. elected since the summer conference: Harold Finegold, Instructol. in Chemistry, Boston University, Boston, Massachusetts. Donald F. Hornig, Professor of Chemistry, Brown University, Providence, Rhode Island. Margaret M. Parks, Associate Professor of Chemistry, University of Rhode Island, Kingston, Rhode Island. Eugene'G. Rochow, Associate Professor of Chemistry, Harvard University, Cambridge, Massachusetts. J. H. Shrader, Eastern Nazsrene College, Wollaston, Msssachusetts. Newell N. Toothaker, Teacher of Chemistry, Sanford, Maine.
President Gifford read a summary of the financial statement of the 14th Summer Conference, an abridged version of which follows: Receipts: Registrations . . . . . . . . . . . . . . . . . . . . . . . 8 782.00 Hostelry . . . . . . . . . . . . . . . . . . . . . . . . . . . 1744.50 Exhibitors. . . . . . . . . . . . . . . . . . . . . . . . . 125.00 Total Reoeipts.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8651.50
Maurice M. Whitten, Lewiston High Sohool, Lewiston, Maine.
268th MEETING
On December 13, 1952, the 268th meeting of the NEACT was held a t Boston College, Chestnut Hill, Massachusetts, as a joint meeting the ~~~t~~~ Association of Physics Teachers and the New England Biological Association. About 200 persons attended. Father John Tobin, S. J;, chairman of the Physics Department of Boston College, presided a t the morning session. The first speaker was Dr. T. E. McCarthy of the Boston College Chemistry Department spoke on "Biology, chemistry, and physics in the medical laboratory." He called attention to some misconceptions concerning the status of employees in medical laboratories, assuring the audience that technologists are not underpaid, nor always assigned routine work. He outlined the various classifications of workers in
152
MARCH, 1953
153
the field, as recognized by the American Society for characteristics of the "outstanding teacher." The Clinical Pathologists, and the training required for each composite being resulting from an appraisal of suggestype of appointment. There are positions available tions will serve as a model to guide the committee of that require only a high school education and others the American Academy of Arts and Sciences in their that require the Ph.D. degree, with all gradations in selection of candidates for the annual award now being beheen. The work is varied also. Besides routine made to outstanding science teachers in New England. tests, that make up the bulk of t,he work for the lower The three associations met separately in the afterclassification of worker, there are among the more noon session. Father James Devlin, S. J., of the Physics advanced assignments, vitamin assays, pregnancg Department of Boston College, spoke before the tests, glucose tolerance tests, determination of calcium NEACT on flame spectroscopy. He took his audience by use of the flame spectrophotometer, all as an aid to through the maze of molecular and atomic structures the clinician in his diagnosis. A great deal of research that are revealed by emission and absorption of energy is also undertaken by those qualified to do it. Dr. in the form of band or line spectra. He demonstrated MrCarthy's remarks were especially helpful to teachers the optical system employed in the analysis of spectra who need accurate knowledge of job opportunities and gave an inkling of the difficulty of interpreting because of their vocational guidance work. band and line spectra. He concluded his remarks by The remainder of the morning session was devoted referring to some applications of spectroscopy as an to a panel discussion on "Judging high-school science analytical tool in the metal industries. fairs." Raymond F. Scott, Rindge Technical High Business Meeting. The President, Dorothy W. School, Cambridge, Massachusetts, opened the dis- Gifford, Lincoln School, Providence, Rhode Island, cussion by defining a science fair as a collection of st,u- conducted the meeting. The Secretary welcomed the dent-prepared science exhibits and by stating that the following members to the Association. This list brings purpose of a fair was to discover potential scientists the number of new members this year up to 47. develop scientific and interests. He ~ ~A. ~ ~m t~nstruetor ,~ . in ychemistry, ~ n i v e r a i t yof Connectidiscussed in detail the criteria for judging that have Storrs, Connecticut, been evolved by the committee in charge of judging of ~ ~ 0Andrew t h Arthur, ~ ~ F. M, S., Teacher of Chemistry, Centr'al Catholic High S~:hool,Laarenee, Massachusetts. the Massachusetts State Science Fair, under the leaderChemistry Depmtment, of D ~~. l bL ~ ~Toft the~ .";emton, ~ ~~ ~~ ~ ~ Oliver ~ L. ~I. Brown, h Chairman ~ ~ of ~ t t ~ , Connecticut College, New London, Connecticut. school s) stem. William L. Davidson, Instructor in Chemistry, Thomas Jefferson Malcolm Campbell, president of the New England ~ i School, ~ hElizitheth, N r n Jersey. Biological Association and a teacher a t the Dorchester Maxwell nf. Erskine, Inntrurto~.in Chemistry, Edward Little High School, A u h u w Maine. High School for Boys, Boston, Massachusetts, was the second speaker on t,he panel, H~ presented his philoso- Morton A. Fineman, Assistant Professor of Chemistry, Providence College, Providence, Rhode Island. phy in directing students in their preparation of exhibits ~h~,,d,,].~ T. Galkowski, Assistant Profcasor of Chemistw, Proviand emphasized fair play on all sides. Elbert C. dence College, Providence, Rhade Island. Weaver, Phillips Arademy, Andover, Massachusetts, Norman G. Mills, Teacher of Chemistry, South Hadley High School, South Hadley, Massachusetts. concluded the discussion with suggestions of exhibits John Osterman, Head of Chemistry Department, Hingham High which he, as a judge, ~vouldlike to see among student School, presentations. He prefers projects which require sister de Florence, A. S. U., Srience Teacher, St. Joseph measurement, as distinct from poster exhibits, that may Academy, Salem, Massachusetts. have great dramatic appeal but little science. Among Sister Mary Adele, Teacher of Chemistry, St. Ann's High School, Gloucester, Massachusetts. his suggested projects were the following: develop- Sister Nativitas, S, S, J,, St, Mary's High ment of pH indicators from coloring matter on postage Brookline, Massachusetts. stamps or from natural vegetable sources; determina- Sister Mary Philemon, R. S. nf.,Instructor, S h e Regina College, Newport, Rhode Island. tion of the characteristics of the local water supply and the used to make is of P. Conant Voter, Chairman of the Chemistry Department, Middlebury College, Middlebury, Vermont. electroP1atillg processes; determination of the effi- Lewis T. Voultos, Instructor in Chemistry, Middlebara Memorial ciency oC various commercial thermal insulators, such as ~ i school, ~ hMiddlehoro, ~ ~ ~ ~ ~ ~ h ~ frozen food containers: and the analvsis of the con- Eleanor R. Wehster. Instructor in Chemistry. .. Wellesley College, .. st,ruct,ion of various hdusehold appliances. He hopes Wrllesley, Massachusetts. for the day when the student-exhibitor will present Phyllida M. Willis, A~sintantProfessor of Chemistry, Wellesley College, Welledey, Massachusetts. as part of his exhibit, his day-to-day notebook of meas15th Summer Conference. President Dorothy W. urements and observations as well as a working model of his device. Onlv if the standards of iudeine are Gifford announced that the Executive Committee has changed will students feel it advantageous to offerV9uch accepted the invitation from Bowdoin College to hold "homely" exhibits, but the scient,ific achievement of the 15th Summer Conference on its Brunswick, Maine, campus during the week beginning August 23, 1952. the fairs will be enhanced; F1et)cher Watson of the Graduate School of Educa- John E. Cavelti, Head of the Chemistry Department of tion, Harvard University, made an appeal to the teach- Allegheny College, Meadville, Pennsylvania, and Guy ers present to draw up a list of personal and professional F. Burrill, Keene High School, Keene, New Hampshire,
~
~
154
will serve as co-chairmen. Auyoue wishing further information about the summer conference is invited to write to the Secretary of the conference, William 0. Brooks, Technical High School, Springfield, Massachnsetts. The secretary presented a r6sum6 of the activities of the Subcommittee on Chemistry of the School and College Study of Admission with Advanced Standing.
JOURNAL OF CHEMICAL EDUCATION
This study has been sponsored by eleven liberal-arts colleges and the Massachusetts Institute of Technology, to seek a method of granting advanced standing to exceptionally well prepared students from secondary schools at the time of their admission to college. It was voted that the Kew England Association of Chemistry Teachers express its enthusiastic support of the work of this subcommittee.
