Tested Overhead Proiection Series Compiled by HUBERT N. ALYEA Princeton University
A NEW TOPS KIT To orient those readers unfamiliir with the TOPS series,' quotations from the article in the series, THIS JOURNAL, 39, 12 (1962), is an appropriate introduction. "TOPS" (Tested Overhead Projection Series), a series on overhead projection of chemical experiments2 is hereby launched. The teacher uses drops; the student sees them on the screen live, in color, as huge as baseballs in test tubes six feet tall and two feet wide. Invisible macro-reactions become clearly visible 100 feet away. This is truly something new under the sun." The various devices in which these are carried out are then described. "Cells: correspond to large beaker8 or lecture jars in macro-demonstrations. Electrical devices: includes electrolysis, ion migration, electroplating, and EMF measurements. Gas devices: replace gas generators and pneumatic troughs in macro-reactions. Heating devices: heating I-IgO, Nz04, FeC++, Pharaoh's serpents, etc. Horizmtalizer: for showing surface tension effects, Na on water, etc. Measuring devices: electrical, pressure, temperature, time, volume, weight." At no time should TOPS displace actual work by the student in the laboratory. TOPS can, however, be used to advantage each week by the teacher during his two hours of lecture, or by the student himself to amplify micro-scale operations during his six hours of laboratory. The author has 40 students using eight TOPS projectors in this fashion. This and three following articles discuss a newly revised (1965) TOPS KIT, containing projectors, plastic devices and chemicals sufficient for 300 different experiments.* Total cost of the kit is under $100, yearly cost of chemicals about $15. COMMERCIAL SOURCES
Commercial suppliers of items for the kit follow. Bottles. Avoid round bottles; use square 2-02 widemouth for solids, narrow-neck with droppers for liquids. Projectors. There are three types. (1) Superior to all others for TOPS projection is the Act-0-Mat,ic 1 The author is indebted to the National Science Foundation for monsorine this TOPS moiect. He is mateful to many teachkrs who'karked with Grn-in Princeton,kspecially to Mi. Albert A. Surina. who bore with him through the trials and tribulations of fashioning many prototypes of devices, and ta Mrs. Lillias Brescia of Manshawkin. N. J.. whose skillful draw+.ings greatly augment the value of the se&. For an extensive bibliography on overhead projection see A ~ m a N. , H., ~ r u JOURNAL, s 33 A541 (1956) and 36, A7534 (1959). 'All of this material will appear in the TOPS reprint, 2nd edition, Chemical Education Publiiqhing Co., Easton, Pa., $2.00; available in mid-June.
Projector sold by Tho Laboratory Furniture Co., Old Country Road, Mineola, N. Y. It has a 5 X 5-in stage which autofocuses vertically or horizontally. Cost, $400. (2) Projectors burning a brilliant quartziodine sunXun lamp, quite fragile, with stage adapters for TOPS devices, but utilizing only one-quarter of a 10 X 10-in stage are sold by Charles Beseler Co., East Orange, N. J., and The Minnesota Mining and Manufacturing Co., St. Paul, Minn. (3M Thennofax model 66, local Thermofax dealer). These models, with TOPS adapter, cost about $170. (3) Simple TOPS projectors suitable for use in a dimly-lighted room are sold by the Central Scientific Co. (CENCO), 1700 Irving Park Road, Chicago 13, Ill.; also by The Macalaster Scientific Corp., Mass.; also by Hugh Wood and Sons, Ltd., London-1, England. Cost about
-. ". SL7n
Devices. All of the manufacturers listed above sell a few of the TOPS devices; CENCO sells the entire set for $125. Plastic. Plexiglas plastic (methyl methyacrylate) and ccinent if not available from your local hobby shop can be purchased from (1) Lorraine Plastics Co., attention Mr. John Estok, Route 23, Robbinsville, N. J., or (2) Commercial Plastics and Supply Co., 127 Freylinghausen Ave., Newark, N. J., or (3) Plastic Products of Utah, Salt Lake City, Utah, or (4) Universal Plastics Co., Seattle, Wash. If black half-inch thick stock is not available, cement two quarter-inch sheets together. Glass parts. A figure showing all the special glass parts required to make the devices will appear in the June issue of this series. These can be made by the teacher, or by the glassblower in your local university. If not available locally, send $6 (price subject to change) to our glassblower, Mr. Nelson Davison, Frick Chemical Laboratory, Princeton, N. J., to cover cost of shipping and manufacture of the eight glass pieces shown in the Figure. Alcohol burners. Kaufman Surplus and Arms Store, 623 Broadway, New York City, att: Jack Bernstein, price per burner $1.25 postpaid; minimum order six burners. A substitute can be made from a wick passing through a notched cork in a small bottle, or by cutting short the spout of a small oil can and inserting a wick, boring a small hole to admit air. Mirrors. Buy the thinnest, optically clear stock available locally. Fish valves. From local pet shops; be sure the stem faces in the right direction. Must have a hole bored in the bottom of the valve. Projector parts. The Edmund Scientific Co., Barrington, N. J. sell parts necessary for making the student and the teacher TOPS projectors. Cost of Fresnel and glass lenses, $9. DEVICES
The thirteen basic devices, 1965 Models, are shown on the next page. Next month's TOPS article will describe how to construct them. Volume 42, Number 5, May 1965
/
A409
E-l
ACCESSORIES
BOX Boric Tops Devices. 1965 Models
A410
/
Journal of Chemical Education
