Chemistry and the Visually Impaired Available teaching aids Dorothy Tombaugh 971 Richmond Road, Lyndhurst, OH 44124 The primarv-purpose of this article is to create an awareness . of pos&bilities for the visually impaired to participate in chemistry. The goal is to better educate handicapped persons in the science ofchemistry and its relation to theother physical and natural sciences. The barriers for blind students wishine to studv chemistrv have been primarily attitudinal barriers based on a concern for safety. This harrier was often based on false assumptions of the abilities and disabilities of handicapped students and is discussed in detail in the last paper in this series. The number of blind persons who have majored in chemistrv to date has been relatively small. A steadily increasing number of visually impaired students are enrolling in one & more chemistry courses as a part of their general education or as a complement to other science courses~~hese groups will undoubtedly increase as new instrumentation becomes more readily availahle. Some blind persons take notes while their laboratory nartners or a lahoratorv aide describe the events of each experiment. Others perform various tasks i n the laburatory as Dart of a team. Still others perform mosr investiantions with a minimum of aid. The handicapoed . . student should have a conference with the chemistry insrrucrur and lnboratory assistants het'ore the first class toclarify the strennhsand needs of the student. The visually impaired also can i s e this opportunity to learn the location of equipment and labware so easily visible to sighted . . students. Seating arrangements in the lecture room may be of importance to the blind student. If friends guide him, a place with them may be helpful. A seat near the front of the room may he preferred for tape recording lectures. If lecturers recite aloud as they write on the blackboard or use the overhead projector, the learning of both sighted and non-sighted will be enhanced. Blind students should be addressed by name when being called upon as they cannot see by the turn of the instructorrhead at ahom thehuestion is aimed. The aid of the blind should be enlisted to make any changes in the laboratory to aid them to work independently as well as with a partner. All reagents used by the visually impaired should have braille or large print labels. Chemicals so labeled should have a dual label in standard print for the sighted nartners and staff. A blind and a siehted nerson should iointlv check the labels to insure accuracy. (upside down braille is a misnomer.) The 3M Braille Labeler shown in Figure 1embosses braille on vinyl tape. The upper rim of the dial has brailled characters, the lower rim has standard print letters and numbers; thus, it is usable by both sighted and nonsighted persons. An interchangeable dial with large black letters is also available. If a labeler is not available, the blind student prepares labels by first typing and then brailling self-adhesive labels. Ricker (2) suggests the use of a baud of sandpaper on bottles containing concentrated acids as a warning symbol and the use of textured containers toindicate other hazardous liquids. Figure 2 shows a labeled shelf with brailled or laree tvDe .. labels. Whether chemistry texts are in print, in braille, or on tape should be decided in accord with the preference of the student. A supplementary text on chemical~calculationsshould also 222
Journal of Chemical Education
Figure 1.3M braille labeler.
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Figure 2. Shelves and reagent battles labeled with braille. he available as much of this instruction often is added visuallv via the hlackboard or overhead projector. Supplementary texts and iournals on taoe or in braille are scarce in the field of science. Most of thismaterial is presented by a reader or read with the aid of an Optacon. In many communities there are volunteers who will braille and tape material on reauest. In small group instruction or tutoring, a braille blackboard is an aid for the student. I t eives space for balancina. equations . and showing structural formulas as well as series of reactions. The hlackboard is simolv a sheet of ulvwood where the student affixes self-adhe&e tapes on-which he has brailled symbols and numbers. By the time visually impaired students enroll in chemistry they should have acquired techniques for solving mathematical problems. A few work problems mentally; others use braille designations on braille paper. Some blind students do calculations usine an abacus. One of them usine-a Japanese . abacus equaled in time and accuracy the work of a sighted student oerformine the same task on an electronic calculator. A l,raill~~ircular glide Rule (3)and an Electronic Calculatnr with braille readout ( 4 ) arc available. The Speech-Plus-Calculator 15) is relatively new. As numbers arepunched into it, the fizurc is audit~lvemitted. This may he operated with an earphone so it is used unobtrusively buring tests. For the benefit of sighted instructors aiding visually impaired students in problem solving the Brannan Cubarithm Slate or the
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Figure 3. Making a raised line with a stylus on braille graph paper.
Figure 4. A regular darkroom clock-timer being conwelted to a raised-lener
Figure 5. An example of standard equipment whose raised markings make them usable to the visually impaired.
felt or on a heavy rubber mat to allow lines to be indented in the uaner . . as thev are drawn with a variety of tools. Braille paintings are made on cardboard by outlining a pencil sketch witb Elmer's" glue. String, wire, and buttons are among the small items inserted in the glue to vary the texture (7).Multiple copies of raised-line drawings are made with the American Thermoform Brailon Duplicator (1,8). When equipment is to be demonstrated, the visually imnaired should be eiven an ouoortunitv to examine the aDDa;atus before the lecture. ~ h kwhen , aiecturer discusses what occurs a t the cathode, the non-sighted can visualize the happenings. Drawings in laboratory manuals for the visually imnaired are seldom detailed sufficiently t o show all items. If equipment is set-up for the experiment, not for the blind to use, hut as a model or a 3-D picture, it will aid all students. Visually impaired students quickly become proficient in the of the centieram balance with a t a ~ e dmiduoint. A ~ - use ~ finger placed on the tape locates the pointer as it comes to rest. The weights on the beams slide into notches. These are readily counted by touch to determine the value. For the slide with no grooves, the student's braille ruler can be calibrated witb the scale so 1cm equals so many milligrams (9). A suitable timing device is the big wall timer with second and minute hands aesigned for m a n t h operation which often is used in darkrooms. Elmer's" glue is added a t the lines indicating the time divisions and to make raised numhers (see Fig. - 4). A kitchen timer with raised or depressed lines and the student's braille watch serve for some occaiiuns. A variety uf commercial timers including stopwutches are a\.ailahle with hrsille numerals .. ~ ~ (1.3.4). ~ . ~ . . ~ For linear measurement non-sighted persons provide their own braille ruler wirh Knglish and metric units. For greater distances a maple meter stick with brads nailed a t eachdecimeter serves. The intervening distances are determined by counting the depressed cm a i d mm lines or measuring with ~~~~
version by adding Elmer'seglue.
British Taylor Slate are available (3). A Braille Scrabble Board (3,4) with the addition of a homemade set of numbers will also serve. I t is interesting to note the variety of computational aids available internationally ( 6 ) . It is important for all students to take tests at the same time rather than to have their busy schedule of activities interrupted for individualized examinations. Students listen to tape-recorded tests via earphones so as not to disturb others in the room. Final exams can be brailled for those that so desire. Most visually impaired persons write script readily enough to answer objective and short answer tests. For essay questions a typewriter can be brought into the room or the student can type in the chemistry office. Test grades should be made with the Braille Labeler and affixed to the bluebook or posted with a brailled name on the grade list. The handicapped should not be exempt from any laboratory investigation. The same caliber laboratory report is expected from the visually impaired as fromthe sighted. All reports are expected to be typed, to include tables of data, graphs, calculations and sketches of apparatus as appropriate for the investigation. Graphs are done on braille graph paper (Fig. 3). A tracing wheel or stylus is used to conned points. If sketches of equipment are to he included, the non-sighted make raised-line drawings of the apparatus. Raised-line drawings are made to show what is visible in sketches in the text, on the board and on the overhead projector. Braille paper is placed on a block of wood covered with
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of liquids are determined accurately by weighing. This requires consideration of the density of the solution. Small nlastic heakers are suitable containers in which to weieh the liquid. Syringes are an easy way to measure liquids. Notches can be made on the plunger of a plastic syringe to indicate various volumes. Ricker (2) placed the syringe in a clamo on a rinestand next to a dowel rod marked to indicate amounts. Several Variable Volume Dispensers in plastic are available commercially. These may be set to deliver from 5 to 25 ml of
Volume 58 Number 3 March 1981
223
Flg~re6 Tnreeava able llghl sensors i n g h f r f r ~ rSen n Fr~nc*scoLlght Ho~re the Blond (center from Sc eneo for the Blma PGd~cfrand llehl lrom Amercan P m r ng h o s e far the B nd See LlteratJre Cltea for amresrer al
101
Figure 7. Light sensor being used as a iiqud level indicator in conjunction wilh a probe.
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liquid. The raised markings on the plastic indicate amounts so the visually impaired are able to use this lahware unaided (Fir. 5). Fhe'light sensor is a small photocell protected by a case with an opening in one end to allow light toenter (3,4,1O, 11) (Fig. 6). When it is switched on a continuous tone is emitted. The pitch of the sound increases with the brightness of the light. An earphone may he used with two of these instruments (4, 10). The light sensor detects differences hetween a clear and cloudy solution to indicate the formation of a precipitate. It gives a different tone to show a change in color to indicate the endpoint of a titration. Locating the meniscus of a clear solution depends on the lighting hut it can.he done. It may he expedient for the sighted or aid to describe reactions involving color change. There is currently no simple instru.merit to read the color of a solution or object. Somuch depends Ion the individuals' tone discrimination, amount of practice and other oersonal factors that each case reauires a senarate :assessment. Obvious changes such as a light yellow solution of iodine changing to dark blue when starch is added is easily discerned. Using greater amounts of indicator aids in distineuishina a colorless solution from one that is pink with uhenolthalein. Several accessoriesare available to use with one light sensor, the Audicator (4). There are Clip Leads for checking circuits, a Light Sensor on a cable for monitoring lights, a Reverse Polarity Switch for electronic applications and Liquid Level Indicators. The laboratory style Liquid Level Indicator (Fig. 7) consists of a stainless steel nrohe on a cable connected to the Audicator. When liquid comes in contact with the probe, a circuit is completed and the Audicator emits a squeal. This is used to precisely fill a volumetric flask or graduated cylinder. An amount of liquid a little short of the desired amount is poured into the flask or cylinder. The probe is then clipped in place at a pre-measured location. The final amount of liquid i s added with a dropper until the sound from the Audicator is heard. Handicapped students are concerned for their safety hut not fearful. Blind persons who have built campfires and cooked over an open fire as well as on a gas stoveneed little direction in lighting gas burners. For a few, electric hot plates mav .be ureferahle. . An introductory experiment often involves observations of a burning candle. Class discussion of this give the visually handicapped an opportunity to offer observations seldom made by sighted peers. The Black BOXinvestigation often teaches the sighted the value of listening. For some reactions we say, "Lmk to see if the solution turns cloudy," when we mean "Is there evidence of a precipitate?" Bv filtering the solution, the non-sighted examines the filter for evidence of a precipitate. The quantities of reactants 224
Journal of Chemical Education
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liaht " .orobe alone to determine liouid level in a Dlastc or& uated cylicder having raised ienering on the outside. Accuracy from f 1 or 2 ml varies with the experience of the operator and the type of probe used. Fioure 8. Usino the
need to he increased to insure a sufficient quantity of precinitate to be determined manuallv. To f11ter.a fineer .. is olaced . near the t q uf~ the illtrr paper todetermine the level to whirh the material is ooured. (Obviouslv this method is not meant f o r highly poisonous o r corrosive substances.) An alternate technique is to retrieve the precipitate from the bottom of a centrifuge tube and feel the solid as it is pressed against the side of the tube with a stainless steel spatula. The sense of smell is often neglected as a means of ohsenring chemical change. Blind students and others should learn the technique of wafting an odor to them. This should not he reserved for the experiment on preparation of esters. Most eases cannot he seen even hv the siehted. In an ex" " periment involving the generation of a gas, the visually impaired can determine the volume of gas by weighing the water in the gas bottle before and after the gas evolves. Gas collected in a plastic hag from a gas cylinder is weighed by the blind students without assistance. Models help all students visualize the magnitude of 22.4 1of gas. Organic, atomic, and crystal model kits are important learning aids for all students, and they are especially appreciated hv the visuallv imoaired. The atoms carbon. hvdroeen. onygen,and nitrogenaredifferentiated by the numbeiof hkes in the wooden ball^. Halogens w r r altered by adding 11rads in a different pattern for fluorine, chlorine, and iodine. It is desirable to alter the surface of the wooden halls with hands of tape of various textures to make the general structure of the molecule more auuarent. For cwstals the surface of each kind of atom should be of a differe;t texture. The tactile models for the use of the visuallv. impaired are best acquired hv al. tering existing kits. The changes made in these in no way interferes with the learning of a iizhted person using thrm (see Fig. 9).
Figure 9. Addhional shapes which can be made to s p e e d h assembly of wganic moiecule models.
I i Figure 11. Thermovoice from the American Foundation tor the Blind with two pmbss: -10 to 100'C and 27 to 250°C.
Figure 10. The Aud-a-mometer with the bralledial for the null indicator connected 10 a stainless steel probe to determine temperature.
The visually impaired person performs some chromatography experiments unaided. The light sensor is able to locate the spots of amino acids after treatment with ninhydrin if the solution of amino acid is strong enough to give a distinct purple color. 'l'he paper is notched with scissors to mark the location uf the various solutions, base line and solvent front. A tracing wheel is used to outline the location of the sporsso thar (hey can be located to measure for calculatiuns. In a rwiew ofexperiments for i n t r d u c t u g highschool and college chemistry courses, it was noted that the thermometer is used in more experimenW than any other device which is not readily available fur independent use by blind students. The Aud-A-Mometer (4) is a braille thermometer with a variety of stainless stwl probes for various ranges (see Fig. 101.For a -10 to 1 IO°C ranre the accuracy is f l°C in the middle of the range and f20e a t the ends with good tactile sense for reading the braille scale. A clinical Aud-A-Mometer with a range of 35OC to 43OC has a iO.l0C accuracy. Greater accuracv is available for the laboratory Aud-A-Mometer by using a series of short range probes with the wide range determiner of temperature. The Aud-A-Mometer operates with a Null ~ndicator.A tone is reduced to no tone when a knob on a dial with a hraille scale is turned to the reading registered by the stainless steel probe (4). ThermoVoice, a talking thermometer, is expected to be available late in 1980 (3).It, too, will have alternate probes available for ranges sufficient for a laboratory, clinical, indoor-outdoor. and a cooking thermometer (see Fig. 11). ~ h e r m o ~ o ihas c e an accuraLy of i0.I0C. It is housed inn small container which can he worn on a cord about the neck. This makes it readily available to the blind person. The probe tip stabilizes in seconds after contact with the material to be tsated announces the measured temwera..... and ThermoVoice ture. When its hatteries need recharging it reminds its user savine. -~ -."Low.. .law... Low.. ."This thermometer may also be heard via an earplug. ~
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Figure 12. The weight buret.
Techniques to enable blind students to perform titrations have been described by Hiemenz and Pfeiffer (12) and by Tallman (13) in this Journal. The weight-buret described by Seils, Meyer, and Larsen (14) was designed primarily for accuracy. I t is also a suitable technique for visually and orthopedically impaired persons. A plastic washbottle is converted to use as a weight-buret by warming the tip and drawing it out to a fine point. The washbottle is filled with titrating solution and weighed before and after the titration (see Fie. 12). Weiahinn, instead of taking readings on a con;entiona buret, e l i h a t e s the need to stand or to see. The blind determine the endpoint by the change in sound of the light sensor. With a Voice Synthesizer (5) attached to most instruments in the laboratory the visually impaired will soon be able to function with proficiency and independence in the chemistry laboratory (15). Werner (16) states any instrument having a Binary Coded Decimal (BCD) output may be interfaced with the "talkine box." The Sareent Welch nH Meter. Mettler Balance, ~ l t t l e~r l e c t r o n i c h u n t e r0h'aus , ~lectronicBalance. Sareent Welch Soectro~hotometerand other instruD to be interfaced with men& may be specified k t h B ~ output the Voice Svnthesizer (16). This instrumentation will do much to increase the inde~ e n d e n c eand redure the barriers fur the visually impaired person in the chemistry laboratory. ~
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Literature Cited (1) Clewland (and other localitier) Society far the Blind, 1909 Enat 101 St.Cleveland,
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121 R r k e r . Kcnnslh 5 . Rcmurre Manual Tearhna Dioiom lo Vmual.! Handrapped
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Luornu." L'","rn,,, dOrlr*,.. t h c n a . ti4 30F* 2. IOIO. I'rxmti.fur Pcoplcu#thV#rmnI'n~hlrm~."C.rsiwr Amm?an Favndnlianforths
Volume 58
Number 3 March 1981
225
Blind,l5 West 16th Street,NewYork, NY 1W11.FdI 1979. 14) Benham, Tom, "Science for the Blind Product%." Cetdogue, Box 385, Wayne. PA
(81 Thermofsx Corwmtian. 8540 E. Slsusen Aue., Los Angdes, CA 90660. (91 Tombaugh. Domthy."CollegeBiologyfor the Blind,"Proceedinga o f C h o n g ~ S t ~ f ~ g i e 8 and Dr8oblrdPersons:PoslseeandoryEducolion nndBwond. Pat M a w IEdirorl, University Publieations Wright State Univwrity. Dayton. OH 45431,1978. (LO1 "CataiogofEdueationalandOthe~Aids,"AmerieanPrintingHousefortheBlind.1839
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Journal of Chemical Education
Frankfort Ave.. Louirville, KY 40206,1986. (111 Nelnnn, David W.. Light Probe: "Instruction Manual and Suggertd Uaea: Sen Franeireo Liehthouse for the Blind, 1097 Haward St.. San Fisneism. CA 94103. 1979. 112) Hiemenz, Pnul C. and Elizsbefh Pfeilfar, "A Oenerd Chcmirtry Experiment for the Blind? J. C H E MEDUC., 19, 263 (19721. 1131 Tellman, Dennis E., "A pH Titration Apperstus for the Blind Student," J. CHEM. EDUC.55.605 (19721. (I41 Seilr. Jr..C. A.,Meyer, R. LandLarsen, R. P.."Amperome~ieTiwationafPlutonium IVLI with Iron(Il): Anolyricol Chemistry, 1673 (October 1963). (151 Salt, Alger. Lunnay. D., and Hartners. R., "A General Purpose Talkinghbomtory Instrument lor the Viruelly Handicapped,'. East Carolina University, Gremville, NC 27834. 1980. (161 Werner, Mark, Sergent Welch, 9520 Midrveaf Avmus, Cleveland. OH 44125.
