Future Reflections Fall 1995, Vol. 14 No. 3



by Kathryn E. Hill

Editor's Note: The following article was originally published in The Educator, 6 (1), under the title "Practical Science and Drawing Science Diagrams with Blind Students Integrated into a Nigerian Secondary School." This publication of the International Council for Education of the Visually Impaired targets educators and researchersChence the rather dry title. However the article is easy to read, the tone is upbeat, and the suggestions for adaptations are sensible and relevant.


The Boys' Secondary School, Gindiri, Nigeria, was the first Nigerian Secondary School to integrate a student who is blind and thus open up secondary education to blind Nigerians. This was in 1957 and the blind student, Bitris Gani, gained a Division I Certificate in his West African School, which included a credit in Agriculture Science. He went on to study Physiotherapy at the London School of Physiotherapy. Other students who were blind followed him into Gindiri Boys' and other Secondary Schools.

As far as science is concerned, they were and are mainly restricted to Health Science or Biology, with a few students branching out into Agricultural Science. For blind students this science was, and largely still is, restricted to the theoretical parts of the syllabus, with practical work and diagram drawing considered impossible of students who are blind. The West African Examinations Council excuses candidates who are blind from practical papers in science subjects.

The author taught Biology, Chemistry, and Integrated Science at Boys' Secondary School, Ginidiri from 1978 to 1990 and became interested in involving students who were blind in practical work and diagram drawing. The apparatus and techniques used for the teaching of diagrams and of two science topics are described.


The various science syllabuses are rich in diagrams which the student is expected to draw. This includes copying from the text book or blackboard and drawing actual specimens, sets apparatus, etc.

Using a smooth rubber mat, a suitable plastic or Melinex sheet, and a special drawing tool, students who are blind can be taught to draw. A raised (feel-able) line is produced. However, this imported equipment is very expensive so local alternatives were sought.

Car mats (smooth on one side and available freely) cut into four make suitably-sized mats. The elaborate system of clips, pins, etc., used to fix the drawing sheet to the imported mat can be replaced with a film of water which holds the plastic sheet in place (and is, itself, a good demonstration of the use of surface tension).

Various types of polythene sheets were bought and tried. The best turned out to be the polythene which a local firm (Nkasco) used for their corn flakes. They kindly donate rolls of this from time to time and it is cut to size. This polythene is stiff enough for labels, titles, etc., to be Brailled directly onto it.

An ordinary biro which has run out of ink, and which would normally be thrown away, makes an excellent "pencil," and at little expense you are ready to draw.

Two sets of apparatus are needed, one for the teacher and one for the pupil. The diagram is built up step-by-step with the teacher drawing a line, the student copying it, the teacher adding the next line, the student copying that, etc. This is labor intensive and time consuming, but is worthwhile as it is an enormous help to concept formation as well as giving the student more complete access to the curriculum. It is important to keep it simple as the eye loves detail but the finger is confused by it. Diagrams, therefore, need to be reduced to their bare essentials. With beginners, a single line is often used in place of the normal double line. As students become more competent, more detail can be included, more of the diagram can be drawn at each stage, and conventions such as double lines observed.


This topic involves students in practical measurement of length, volume, time, and temperature. Techniques and locally made/adapted apparatus have been devised for the first three of these.

(a) Length: An ordinary wooden ruler, as used by most of the sighted students, was notched at 1cm intervals using a razor blade. The blind student can now measure to the nearest 0.5cm - the same degree of accuracy as with the imported plastic rulers. A standard meter rule is turned into a tactile instrument by hammering cut-off pin heads at 1cm intervals. This can be extended to having two pins at each 1cm, one pin at each 0.5cm, and three pins at each 10cm. Tape measures are readily available in the market. These can have holes punched at 1cm (or 1 inch) intervals, like the imported ones, or, even better, have a staple fixed at each 1cm mark.

(b) Volume: The above apparatus can be used to measure and calculate the volume of regular objects but different techniques are needed for liquid volume and irregular objects. Now there are two methods of measuring liquid volume. The first is when the total volume of a liquid is measured; the second is when you wish to measure a stated volume of a liquid. Both are possible to some extent for people who are blind. An imported light probe can be used to accurately determine the level of liquid in a measuring cylinder with tactile markings. Without a light probe, an estimate can still be made. Graduated beakers of various sizes are marked by super-gluing small pieces of gravel on the marks on the inside and then varnishing them with clear varnish. Using their fingers to determine the water level, and knowing the interval between each tactile mark, the student who is blind can make a very rough measurement of the volume of the water. This has a number of disadvantages as it is not accurate, and can only be used with harmless liquids, but it does convey the concept of the use of the measuring cylinder. In the same way a very rough measurement of the volume of irregular solids can be made by finding the volume of water, adding the object, and then finding the new level. Again this is far from accurate but the concept is conveyed far better than by a mere description. In place of a pipette for measuring out accurate amounts of liquid, a plastic syringe can be used. These syringes can be imported ready notched with tactile marks or friends in the medical field can be asked to save used syringes which are easily marked and notched with a razor blade to enable the accurate measurement of various volumes. By using large and small syringes, accuracies of 0.1cm3 can be achieved (see "Titration" below). Students who are blind easily learn to use a syringe pipette and are delighted to find they can be as accurate as their sighted peers.

(c) Chemistry Topic - Titration: At first sight, titration might seem impossible for the Nigerian chemistry student who is blind because of the need to see a color change in the indicator; this observation would only be possible for a student who is blind with the aid of a costly imported talking PH meter. The solution was to use a human talking PH-meter so that a teacher or a fellow student who, after a student who is blind adds the appropriate acid to the experiment, simply says "no change" or "change." One could argue that if the student who is blind does not have to determine the end point for him/herself, the experiment is easier for him/her; but it can equally be argued that the problems blindness cause in accurately carrying out the rest of the titration techniques are an "equal but opposite" disadvantage and thus evens things up! Certainly, it is better for the student who is blind to perform this modified titration than to simply work with other people's results.

A plastic beaker, labeled with a Braille A, is used for the acid and a glass beaker, labeled with a Braille B, for the base. Using a large syringe-pipette the stated volume of base is measured into conical flasks and indicator added in the usual way. The rough titration is made adding acid 1cm3 at a time from a large pipette notched at 1cm3 intervals. When the fellow student says "change," the total volume added is noted. A volume of acid which is 1cm3 less than this amount is then added to the second flask. The blind student then changes to a 1cm3 syringe-pipette which is notched at 0.1cm3 intervals, and adds 0.1cm3 at a time until the fellow student says "change," when the total volume is again noted. This is repeated until good replicates are achieved. An experienced blind chemistry student using this technique can achieve results every bit as good as the best of his/her sighted peers.


With ingenuity, a little money, and much time, students who are blind can be given nearly full access to the practical and diagrammatic aspects of science syllabuses thereby improving their understanding of the subject, and thus enhancing their chances of success in examinations and the quality of their education.