As a science teacher, I have always used models in my teaching. The representation of a 3D object with a 2D diagram is something that most students will understand, and they should also be able to scan and track an animation on a screen.
But when I started working at a school for visually impaired students, I suddenly found that my PowerPoints and animations were redundant for most of the children I was teaching. I was forced to rethink and found a solution that may be useful for teachers in any type of school: a more tactile approach to modelling in science.
Substituting an animation or diagram for a tactile model requires a certain level of creativity and quick thinking, but they can be made very easily and they have a big impact.
For example, when teaching the digestive system I use a knitted version, which can be complemented by a tactile graphic pointing out all the different elements.
When we discuss the small intestine, I use another model made from a bath mat to demonstrate the finger-like projections called villi.
Students are likely to have learned that villi increase the surface area of the intestine enabling maximum absorption to take place. At this point, teachers often talk about the mathematical principles of surface area. However, as the principle of absorption is the most important point here, I take two square swatches of the bath mat fabric, cut off the projections from one and leave the other intact. I dunk them in water, then squeeze out and measure the liquid from each one. The intact sample holds three times as much water as the shaved one. This makes the point quickly and clearly.
Another model I use demonstrates the structure of the heart and cardiac cycle. I fasten Wikki Stix (essentially sticky strips of modified yarn) to a white tray to depict the chambers of the heart. Blood is represented by red beads (some loose and some linked). The Wikki Stix can be adjusted to show the opening and closing of the valves.
It is important to refer to all components using the correct terminology so that students associate the appropriate language with their tactile memory of the model.
Education consultant Lucia Hasty suggests that sighted students will look at the whole picture then focus in on its parts, whereas a visually impaired student will absorb information in reverse: they encounter the various parts and then use them to construct the whole image.
Using tactile models in the way I have described helps visually impaired students to make sense of a concept because it addresses Hasty's point. It could also be a useful tool for reinforcing understanding among sighted students.
Sarah Hughes is depute head teacher at the Royal Blind School in Edinburgh and shares her resources at www.tesconnect.comSarahHughes