Project Teaching in High-School Chemistry II. Models and Demonstration Apparatus WILLIAM C. CURTIS Dunbar High School, Washington, D. C. HE CONSTRUCTION of models and demonT s t r a t i o u apparatus develops both the academic and mechanical skills of superior students in highschool chemistry. Such projects offer an e~cellent opportunity for students to plan and carry out their own purposeful and self-directed activities. Moreover, they tend to satisfy the urge to create and enable students to correlate the knowledge and s k i s acquired in other subjects with their work in chemistry. The student should first select a chemical principle, process, or concept or an important application to modern life. A model or demonstration apparatus should then be planned to illustrate or demonstrate the principle or idea selected.' The student should gather or collect as much of the material needed in the completion of the project as possible, men completed i t should be neat, attractive, and dynamicz Carefully planned inspection trips to such museums as the New York or Chicago Museum of Science and Industry and the National Academy of Sciences, Washington, D. C., will serve to familiarize the students with examples of skilfully constructed and protected scientific exhibits. Close-up pictures of chemical plants and laboratories and their surroundings are of tremendous value to students the construction of models. Some examples of suitable models and types of demonstration apparatus which high-school chemistry teachers may appropriately lead their students to "discover" are given below. Many of these should prove of value in connection with our defense efforts. Some of them can be used for instructional purposes. Others may be useful in working out local camouflage and blackout problems.
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(12) High explosive bombs. (15) (16) (17) (18) (I9) (20) (21) (22)
(23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37)
Cf., Sci. Lcaflct,
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(1) Adsorption. Cf.,ibid., 18,432 (1941). (2) Aluminum extraction. Cf.,ibid., 18, 193 (1941). (3) Alnba-rav track anoaratus* ~ i l a n c e . . Cf.,i b k , 10, 118 (1933); ibid., 17, 227 (1940). Conductivity of metals.* Conductivity of solutions and fused salts.' Cf.,ibid., 17, 381 (1940). Colloid cataphoresis. Cf,,ibid., 6, 334 (1929); Sck. Sci. Malh., 36, 502 (1936). Constant temperature oven. Cottrell process of smoke precipitation.* Cf.,J. CHBM. Eouc... 5.. 1001 (19281: . .. Sci. Leaflet. . . 14.. 812 (1941). Densi~yof liqu~ds.' 1)estructive distillatiun of coal and woud. I h y cell. Cj. J. CHEM.E~uc., 6, 7 3 (1Y2H) Electric arc. Electric furnace (resistance, induction, or arc type). Electric glass cutter. Electrolysis of sodium chloride (Nelson or Vorce cells). Electroplating.*
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Bomb resistant shelters. Bromine extraction plant. Coal mine. Cf.,ibid., 13, 6 (1939). Coal tar plant. Cf.,J. CHEM.EDUC..5, 1112 (1928). Cyclotron. Dioramas. Cf.,ibid., 13, 412 (1936); ibid., 17, 397 (1940). (a) Famous chemists and their laboratories. (b) Early and modern chemical laboratories. Frasch process. Cf.,ibid., 8, 630 (1931); ibid., 10, 309 (1933). Gas plant. Gasproof shelters (ventilated and non-ventilated types) Glass factory. SHAW.American Physicr Teacher. 7, 165 (June. 1939). a Cf,,CURTIS, J. CHEM.EDUC.,18. 283 (1911).
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DEMONSTRATION APPARATUS
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Iodine plant. Incendiary bombs. Liquid air plant. Liquid ammonia plant. Cf.,ibid., 8, 2062 (1931). Liquidcarbon dioxide Lime kiln. ~~~~f~~~~~~ of steel,* (a) Bessemer process. (b) Open hearth process. Manufacture Of acid. (a) Contact process. Cf.,ibid., 8, 2239 (1931). (6) Lead chamber process. Cf.,ibid., 18, 47 (1941). Manufacture of rayon. Molecular still. Nitric acid plant. Paper makingmachine (Fourdrinier). Pasteurization plant. refine,,,. Refrigerating machine. Respiratory calorimeter.
Solvay process." Sewage disposal plant, Cf,,ibid., 17, 167 (1940), Synthetic plant. Synthetic rubber plant. Typical oil field. Unexploded bombs (model showing how to detect the presence of unexploded bombs). (38) Water purification plant. (a) Aeration plant. (b) Chlorination plant. (6) Filtration plant.* (39) Water works plant.
MODELS
Atomic and molecular structures.
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* References on marked items are given in J. CKEM.EDUC..17, 389 (1940).
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(18) (19) (20) (21)
(22) (23) (24) (25) (26) (27) (28) (29) (30) (31)
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(32), (33) (34) (35) (36) (37) (38) (39) (40j (41)
Fireless w k e r . Fixation of nitrogen.* Cf.,ibid., 10, 348, 498 (1933). Gas mask. Cf.,did.,19, 322 (1942). General behavior of gases. (a) Boyle's law. Cf.,&id., 18, 15 (1941). (6) Charles' law. Cf.,ibid., 15, 394 (1941). ibid., 12, (6) Laws of partial pressures and diffusion. Cf,, 355 (1935). Hot plate.* Hydrogen sulfide generator (adorless).* Hydrometer. Hygrometer. Magnesium extraction. Oudin coil. Cf.,Scimce Observer, 2, 16 (1940). Ozonizer. Cf.,J. CEEM.Eouc., 5, 1493 (1928). Peltier effect. Photoelectric cell.* Polariscope. Cf., S c k e Observer, 2, 6 (1940); Chm. Leajlet. 15, 1020 (1942).. Potentiometer. Spectroscope (prism or grating type). Cf.,Sch. Sci. Math.. 41,346 (1941). Sensitive flame. Telescope.* Telsa coil.' Tyndall effect. Ultramicroscope. Cf.,J. CHEM.EDUC.,18, 378 (1941). Ultraviolet lamo. Vacuum pump. Voltaic cell. SCENERY SUGGESTlONS
Groundwork-built on corrugated cardboard with wooden frame. 1. Irregular surface-scraps of cardboard with tapered edges or cloth painted with wax. 2. Earth-plaster or plastic paint molded over a base of wire screening or burlap and painted ground color with
various shades of brown, water-soluble, inside wall paint or sifted earth on glue or paint. A damp or wet effect may be obtained by using the latter method and applying shellac after the glue or paint has dried. 3. Grass--sawdust dyed in two or three shades of green with artist's oil colors and glued to groundwork, hemp, dried g~asses,thin strips of paper. 4. Shrubs and t r e e s s m a l l dried plants such as dyed Norwegian lichen, gypsophila (baby's breath), steel wool sprayed with glue and sprinkled with olive green sawdust, sponge rubber, etc. 5. Snow-paraffin wax. 6. Water surfaces-ripple glass, plain window glass, old mirrors, crumpled foil from cigaret packages, thin or heavy sheets of celluloid, paraffin wax colored with oil paint. Building-wood, corrugated cardboard, cardboard or congoleum cork painted with water color. Figures-ature made of twisted wire, Plasteline (permanent modeling clay), or pipe cleaners (for small figures) painted with thick water colon. Navel lighting effectsPrismatic a m . SOURCES OP CONSTRUCTION MATERIALS
DuPont PLastacele (an excellent protective material)-Arthur & Bro., 67 West 44th Street, New York; Maxwell Display Carporation. 240 West 40th Street. New York. Electric Motors. Mechanisms, etc.-Merkle-Kofl Gear Co., 211 North Morgan Street, Chicago, Illinois; Speedway Manufacturing Co., 1839 South 52nd Avenue, Cicero, Illinois. Lumber Supplie-T. A. Foley Lumber Co., Paris, Illinois. Metal Goods-Metal Goods Corporation, 5249 Brown Ave., St. Louis, Missnuri. Modeling Clay-Western Stoneware Co., Manmouth, Illinois. Plastic and Water-Soluble Paiuts-Sherwin-Williams, Graphic Arts and Disolav Division. Cleveland. Ohio. Prismatic ~ i l m l o b t a z~ a n u f a c t u r i n gdo., 206 Broadway, New York.
