How to be more visual in your lectures or tutorials: "One drawing is worth a thousand words"

Drawing is a powerful tool used to communicate, transfer information and solve problems, by its affect on our senses. It is an integral part of the human experience. Approximately eighty percent of our sensory input comes from our visual system. Much of what we learn and experience is through our visual sense. Much of our technological world could not exist without the use of graphics to plan, produce, market, and maintain goods and services.

Visual language is especially helpful to the learning process. There is a tremendous amount of information that can be transferred in a visual way in every discipline, but particularly in engineering, physics, chemistry, dentistry, anatomy, biology, botany, zoology, geography, astronomy and meteorology.

Do we use enough visual expression in our teaching and learning process? Do we know how to effectively do it? We do not need to be experts in drawing techniques to be able to use them in our lectures and tutorials, relevant to our discipline. There are simple techniques and rules, which can improve our drawing skills.

This demonstration session aims to give basic instructions to the Forum participants, on how to be more successful in transmitting knowledge to students, by including a visual mode. No background knowledge is necessary to understand the teaching and learning activity, which will be presented in this demonstration.

Introduction

Figure 1: Application of technical drawing in different disciplines

Technical drawing

To represent an object accurately and precisely we have to "project" that object onto the drawing paper. To "project," means to produce a picture of the object, from reality, onto the drawing paper.

Technically speaking, we have to find all piercing points of the observer's lines of sight through the points of the object and, through the drawing paper onto which it is projected. Among many different types of projections, the five main types are:

1. Perspective: photo-realistic impression.
2. Isometric: pictorial view, not fully realistic but much easier to be done than perspective.
3. Oblique: pictorial view, not so nice as isometric and perspective but very easy to be drawn.
4. Orthogonal: 2D drawing without third dimensions, the easiest one.
5. Contour lines: for drawing maps.

Orthogonal projection represents the picture of a 3D object on the drawing paper when the observer's lines of sight are parallel and perpendicular to the drawing paper (for example, when the observer is above the 3D object in infinity). We can produce as many orthogonal views as we like. However, a minimum of two views is required to define an object in space. As previously mentioned, this projection is the easiest one to create, but some practice is necessary.

Figure 2: Orthogonal projection of skull (side view and front view)

Oblique projection is a pictorial presentation of an object where the observers' lines of sight are inclined to the drawing paper but still parallel. One face of the object is parallel to the drawing paper. It is very easily produced, and is widely used, even by small children.

Figure 3: Oblique projection of table and chair

Isometric is another pictorial presentation. In this case, lines of sight are perpendicular and parallel to the drawing paper. The object is inclined towards the drawing paper. Drawings constructed in this projection are almost like those produced in perspective (photo-realistic); and with simple instructions, these drawings are relatively easy to produce.

Figure 4: Isometric projection of bridge-model, and skin-section

Once we know the rules necessary to produce accurate and precise drawings, we have to learn the techniques. Technical drawings can be done in freehand, manually with rulers, or by computers. In our lectures or tutorials we frequently use the freehand technique. Successful technical freehand drawing does not require talent. It does however, require skills, which can be learned.

Every drawing consists of lines; therefore, it is important that we become accustomed to drawing long straight lines in one stroke. The same rule applies in drawing curved lines, which is to be done with only one stroke.

Furthermore, an attractive drawing on the blackboard is ineffective if our lettering is poor. Technical drawing includes technical lettering. Standard block letters are the most popular and easiest to be read.

Finally, the addition of some colours, and shadows, which can greatly contribute in explaining of our ideas, ensures that information has been transferred to the audience in a very clear and quick way.

Bibliography

Pederson, B. M. (1988). Graphis Diagram 1. Graphis Press Corp, Zurich, Switzerland.

Tortora, J. & Reynolds, G. S. (1993). Principles of Anatomy and Physiology. Harper Collins College Publishers, Seventh Edition.

The New Jacaranda Atlas (1987). Third Edition, The Jacaranda Press.