CHEMISTRY
edited by:
JAMES 0.SCHRECK University 01 Northern Colorado Greeley. GO 80639
C. MARVIN LANG Universliy of Wisconsin Stevens Paint, Wi 54481
Postage Stamps as a Teaching Tool in Chemistry James 0. Schreck University of Northern Colorado, Greeley, CO 80639 The idea of using postage stamps in teaching chemistry is good oedagoav because it associates the subject matter kuAh; with s;&hiny in which the student has on acquired interest. Collecting stamps is a hobby of many students, and those students not oursuine uhilatelv as a hobbv will show signs of interest when certain stamps are brought to their attention. Conseauentlv. " . teachers of chemistw should consider the use of stamps (and in particular chemistry on stamps) to enlist further interest in chemistrv. Interestinglv, this idea was first expressed in a 1934 article ''~hilateiy Serves Chemistrv"': vet. the advice is still timely. chemistry-related'st&nps portray chemists br scientists who have made contributions to chemistry. They publicize important domestic industries including the oil and steel industries, beer makinp-, salt mining, rubber processing, and drug manufacture. chemical symbols, formulas, and structures have appeared on stamps. Important discoveries relevant to chemistry have also been depicted. The purpose of this article is to suggest to the reader how stamps can be incorporated into the teaching of chemistry. The categories listed below are those typically found in current introductory general chemistry texts. v .
Emergence of Chemistry a s a Sclence Democritus (see stamp no. I), a Greek philosopher, was the first thinker to conceive of matter as small, indivisible particles that he called atoms. Dur to .\ristotle's contlirting . ideasond populorityat the time (about 4 6 5 ~ C )l)em~critus' concept &as-not developed until some 2000 years later by John Dalton, who, surprisingly, has never been recognized by the issuance of a postage stamp in his honor. Antoine Lavoisier (no. 2) is generally regarded as the father of modern chemistry and is best known for his rejection of the phlogiston theory. He proposed that, when an object burns, oxveen is removed from air and becomes incorporated into thkburning object. Joseph Priestley (no. 3), a n ~ n g l i s h m a n who immiarated to America, discovered oxygen in 1774 and carbon monoxide in 1799. He is also credited with the discovery of carbonated water by impregnating water with carbon dioxide.2 In 1874, a t a meeting at Priestley's old home that was convened to celebrate the centennial of the discovery of oxygen, plans were laid to organize the American Chemical Society. This organization later estahlished the Priestley medal, one of the highest awards in chemistry. The studiesof Lavoisier, Priestley, and others set the stage for the chemistry pioneers of the 19th century. These pioneers, one of which was Jons Jacob Berzelius (no. 4), would interpret chemical changes in terms of atoms and molecules.
Lavoisier's studies of combustion impressed succeeding generations of scientists with the need for accurate, quantitative measurements. The use of the metric system of measurement is accepted in scientific studies. Stamps have depicted the standard metric units of temperature (no. 5), volume (no. 6), length (no. I), and mass (no. 8). In 1960 the International System of Units (SI Units) was adopted by many countries of the world. A French stamp (no. 9) portrays the seven SI units including the definition of the meter as the wavelength of the orange-red light emitted by krypton-86. A new definition of the meter, based on a unit of time, has since been adopted. The meter had been redefined as t h e d i s t a n c e l i g h t t r a v e l s i n a vacuum d u r i n g 11299,792,458 of a ~ e c o n d . ~ Atoms, Molecules, and Ions The basic huildina blocks of matter are atoms. Atoms are rompoaed of a nucleus and rlectronj that move around the nucleus, often illltrtrated in the rlassiral picture of a11 atom as shown on stamp no. 10. The discovery of radiation by Henri Becquereland Marie and Pierre Curie (no. 11) provided evidence about the complexity of the atom. Ernest Rutherford studied the nature of radiation and established that there were three tvoes: ". a.. ,B.. and v . His experiments on the scattering of a-particles and the bombardment of nitrogen with a-narticles (ea . .1). have been deoicted on the centennial commemorative stamps (nos. 12 anci 13) by the nation of his birth, New Zealaud. The concept of the nuclear atom arose from these experiments. ~~~
:'N
+ :He
-
+
k70 :H
(1)
Atoms are the smallest units of an element. Periodicitv of the elements was first estahlished by Dimitri ~ e n d e l e e ;in 1869. His first periodic table was based on an arrangement of the elements in increasing order of atomic weight andgrouping by similarity of properties. His thinking was quite accurate, and he predicted the existence and atomic weights of eallium and indium, elements that were not actually discovered until years later (no. 14). T o commemorate the centenPresented in a poster session at the 7th ACS Rocky Mountain Regional Meeting, Albuquerque. NM. June 6-8. 1984. ' Schaeffer. H. F. J. Chern. Educ. 1934. 11, 259. Campbell, W . A. Endeavor New Ser. 1983, 7, 141; Miller, F. A. Phiiatelia Chimica 1983, 5, 10. Chem. Eng. News. October 31. 1983! p 21. Volume 63 Number 4
April 1986
283
ldentlflcation and Descrlptlon of Stamps
Stamp No.
Issuing Country
Year of Issue
scan Catalog No.
Greece France United States Sweden Australia Australia Australia AusWalia France Indonesia Sweden New Zealand New Zealand Russia Russia DDR Afars and lssas Belgium Russia Israel Russia Norway Russia France Italy United States United States United States United States Ireland DDR Sweden Great Britain Brazil Spain Sweden DDR Denmark Netherlands Antilles Canada Mexico Canada Mexico Italy DOR Portugal Botswana DDR United States Germany DDR Germany Great Britain Czechoslovakia Russie Malaysia Great Britain
70
286
Gabon China (People's Republic) Israel Belgium Japan United States United States Phillipines Mauritius Great Britain Romania Australia
nial of the Periodic Law formulated by Mendeleev, Russia issued a postal souvenir sheet depicting a draft of the periodic table from his notebook (no. 15). Numerous elemental symbols appear on stamps. Included are N, P , and K (no. 16), Ra (no. 17), and Zn (no. 18). The East German (no. 16) stamp also portrays Justus von Liehig. Among other contributions, he was the first chemist to recommend addition of nutrients to soils. He is now considered to be the originator of the fertilizer industry. Marie Curie (along with her husband Pierre) discovered radium and polonium. Unfortunately, Pierre was killed (1906) before the Nobel Committee awarded the 1911 prize in chemistrv to hlarie for isolnlin:: polonium. Oneof the unique illustrations uf elemental s ~ m h o lis i shown on stamp no. 19. Althoueh the stamp was issued t o publicize thk 20th congr&s of IUPAC held in Moscow, the words "1UPAc"and MOSCOW" contain the symbols of some well-recognized elements. Atoms can combine to form molecules or ions. Examples of molecules on stamps include the isotopes of oxygen (no. 20) and some compounds, NHaN03, NH'HzPOa, and KC1, used in fertilizers (no. 21). Ions on stamps include Ca2+ and Nos- (no. 22) and the complex ion Re2Clg2- (no. 23). This latter species is unique in that i t was the first species recognized to contain a quadruple bond. The interesting history and chemistry of this and other multiple bonds between metals has recently been described.' Stolchiometry
The problem of establishing a relative scale of atomic weights was eventually solved in 1808 when Joseph GayLussac (no. 24) determined that the combining volumes and ~ r o d u cvolumes t of " eases are in small. whole-number ratios at constant temperature and pressure. However, Gay-Lussac did not understand the reason for these relationships. In 1811, Amedeo Avogadro (no. 25) suggested that Gay-Lussac's law implied that "equal volumes of gases, measured a t the same pressure and temperature, contain the same number of molecules". This stamp contains Avoeadro's hvvothesis in Italian along with his signature. Energy Relatlonships In Chemical Systems: Engery Sources
Our insatiahle appetite for energy is predicted to cause a depletion of nonrenewable fuel sources, especially natural gas and petroleum (no. 26). Future energy sources include solar energy, synthetic fuels, and the breeder reactor, which utilizes the latent energy in uranium-238 (nos. 27-29). Gases, Llquids, and Solids
The ~rouertiesof a eas were not svstematicallv studied until the l j t h century Gy Robert ~ o ~(no. i e30) a i d Avogadro (no. 25). I t was not until 1912 that Max von Laue suegested that a crystal should diffract X-rays (no. 31). ~ h ; s stamp depicts a typical Laue diffraction pattern. In 1913 the father-son team of W. H. Bragg and W. L. Bragg (no. 32) obtained and studied the X-ray diffraction pattern of a crystalline solid. An interesting profile of the Braggs has recently h r studies o u ~ hwe have appeared in THIS J o u ~ ~ ~ ~ . ~ Ttheir obtained insight into crystal lattices. A typical example is the unit cell of NaCl (no. 33). Today we can take microphotographs of crystals such as that of a salicylate crystal (no. 34). Electronic Structure of Atoms
Visible light (no. 35) is a form of electromagnetic radiation or radiant energy. . . Frequency and wavelength are characteristics of radiant energy. A study of atomir strurture involves t h ( w chitmctrristics. T h r quantitativr rrlation l~etweenfrequency and energy was developed by Max Planck (no. 36).
1975
Journal of Chemical Education
563
. 60,713. 'Coiton, F. A. J. Chem. ~ d u c1983. Lipson, H. S. J. Chem. Edoc. 1983, 60,405.
Planck's famous constant, h, is depicted on a stamp (no. 37). Neils Bohr in 1914 proposed a theory of the hydrogen atom that incorporated Planck's theory (no. 38). He proposed that when an atom absorbs or emits light in the process of changing its energy, the frequency of the light is related to the magnitude of the energy change by the equation Ez - El = hu. Using such ideas he was able t o explain the line spectrum of hydrogen atoms. Chemical Bonding
In addition to that shown ahove on stamp no. 33, another representation of the NaCl structure has been depicted (no. 39). The ions are shown in their correct sizes relative to the distance between them with the larger spheres representing the chloride ions. A model of uraninite, UOn, which has a fluorite-type structure has also been depicted (no. 40). The planar sp2-hybridized carbon atom in a methyl free radical has been portrayed (no. 41). Nuclear Chemistry
The spontaneous disintegration of an atom (no. 42) and Rutherford's transmutation of nitrogen-14 into oxygen-17 (no. 13) have been depicted. The energies associated with nuclear reactions are obtained with the aid of Einstein's famous equation relating mass and energy (no. 43). The fission of uranium-235 was first achieved in the late 1930's by Enrico Fermi in Rome (no. 44) and soon thereafter by Otto Hahn in Berlin (no. 45). This latter stamp depicts the nuclear equation for the bombardment of a uranium-235 nucleus with a neutron. Geochemistry
Most elements occur in nature in combination with other elements. Stamps have depicted various minerals. Among them are wolframite, a tungstate of iron and manganese (no. 46), stilhite, CaAl2Si7Ols. 7Hz0 (no. 4 3 , fluorite, CaF2 (no. 48), and rhodochrosite, MnC03 (no. 49). Organlc Chemistry
In 1828, Frederick Wohler showed that urea, an organic compound, could he prepared from ammonium cyanate, an inorganic compound. The chemical equation for this conver-
sion and a hall-and-stick model of urea is shown on no. 50. Another German chemist, August Kekule, proposed a hexagonal structure of alternating single and double bonds for henzene in 1865 (no. 51). In addition to the traditional method of representing a structural formula (as that for henzene on the previous stamp), a number of other representations have heen depicted. These include a hall-and-stick models of benzene (no.52), ascorbic acid (no. 53), and adamantane (no. 54), bond-line model of 2-isohutylene-4-methylytetrahydropyran (no. 55), space-filling model of isoprene (no. 56), and conformational model of the steroid nucleus (no. 57). Biochemistry
Stamns depicting biochemical c o n c e ~ t sinclude a Fischer project& o f 8 D-aminoacid (no. 58), stiuctural formula of a penicillin (no. 591, DNA replication (no. 60), and a double helix base pairing (no. 61). Another stamp shows the proinsulin molecule (no. 62). In the hack~roundof this stamp is shown five test tubes illustrating ene edict's test for solutions containing varying amounts of sugar. A protein molecule and mitochondria in the background has also been depicted (no. 63). Laboratory: Apparatus, Equipment, Techniques, lnstrumentatlon
Various types of flasks, a bottle, a test tube, and a mortarpestle have been portrayed (nos. 64-66). Students working in a laboratory without proper eye protection have heen shown on a stampVrom Mauritius (no. 67). A starch chromatographic separation (no. 68), an elertrnn microscope (no. 691, and the rheury of acomic absorption (no. 70) have heen depicted. Actually, innumerable pieces of ~quipmentare shown un a u,ide variety ot'stamps, and it is always a rhallenge to identify the items correctly. The ahove is a brief outline of stamps that can he used in teachine eeneral chemistrv. The stamps chosen renresent the author's preference, hut there are many more stamps that could have been used. Readers will see some of these stamps in future articles in this mini-series. Furthermore new stamps continue to he issued each year. On many stamps it is easy to recognize issues of chemical significance. It is somewhat more challenging to recognize the chemistry associated with stamps that bear no obvious label or title.
-
"rake,
u
R. J. Chem. Educ. 1981,58, A293.
Volume 63 Number 4
Aorii 1986
287
