One of the key decisions I had to make when I designed The Periodic Table For The Visually Impaired was this: how could I make it easier for the blind student to know the tool was properly oriented?
The Periodic Table in use in most classrooms is the classic design, with all of the Reference elements and Transition elements arranged traditionally in a pictorial manner which is longer than it is wide.
That's a lot of pieces to keep track of for a student new to the study of chemistry.
I decided to break the two types of elements depicted into two separate portions.
Namely, I separated those elements in Groups IA to 8A (the Reference Elements) from those in Groups 1B to 8B (the Transition Elements).
I had located adhesive-backed alpha-numeric characters in a craft shop and was satisfied that their dimensions were suitable for fingers to identify.
This was done by closing my eyes and allowing my finger to trace the character's outline until I could correctly determine which letter or number was below my touch.
Satisfied that my student would be able to repeat that process of identification, I then needed to find a suitably durable material onto which to place the alpha-numeric characters.
Checking the dimensions of a standard hanging file folder, I discovered it would perfectly accommodate the 8-column x 6-row grid I needed for all of the known Reference Elements.
(By the time I began my pursuit of the patent for my invention, all of the elements on row 7 had been verified and named; that is when I added row 7.)
I then marked the file folder, using a ruler, into equally-sized blocks, with row 1 containing only two blocks: one in the upper left and one in the upper right, as on the Periodic Tables traditionally used for teaching chemistry.
How should I mark the boundaries of these blocks?
I first tried puff paint, administered through those paint pens; however, that proved too difficult for me, as my hands both have carpal tunnel syndrome after so many years of teaching.
A thick yarn, glued in place, proved to be perfect, as it had a considerably different texture from the file folder's smooth paper.
Next would be affixing the alpha-numeric characters into place.
The craft shop had given me a choice between two makers of the alpha-numeric characters, with each manufacturer's product having different textures, but the same dimensions, of those characters.
One product had foam characters; the other's characters were printed on cardboard, with a slick, smooth surface printed with a colorful pattern (which did not matter, as that would not be visible to the student).
How fortuitous that the two textures had been so readily available!
I decided to alternate the textures, with the slick cardboard characters to be used on the odd-numbered rows and the smooth foam characters on the even-numbered rows.
Those two very different textures would be perfect for allowing a blind student to keep track of the different rows in the Periodic Table, providing them the ability to go from row to row at the same pace as the sighted students in the class.
I then placed the characters into the blocks on the grid, as shown in the above photograph.
Again, the look of the Periodic Table is not the important factor for a blind or low-visioned student; the feel of it is paramount.
For my invention, the feel comes through clearly: an open hanging file folder, laid out into six rows and eight columns, filled with blocks which are approximately 2 square inches and contain alpha-numeric characters that differ in texture in alternating rows.
And how does a student determine from touch that the tool is face-up and oriented with the first row at the top, ready to use?
The student can run their hands along the sides of the hanging file folder, where the metal hooks are, until the student can locate with each hand the single blocks in the first row.
The student then makes sure those single blocks are underhand at the upper left corner and upper right corner, at the top of the Periodic Table.
Ready to use!
How do I know it works?
I closed my eyes and did as the student would do.
(smile!)
