My experience as an engineering student suggests the following rough dichotomy. There are two types of engineering (and physical and biological sciences) professors: those whose presentations are disorganized and confusing so that I learn the subject matter faster by studying on my own. Their worst crime is to come to class unprepared, shuffle through their notes, pick a sheet and start transcribing from the sheet to the blackboard. The students then transcribe from the board to their notebooks. Of course no brain activity occurs in their heads. The second type of professor are those who really help me learn the subject: they stimulate intuition and illuminate the material; they clear the road for my further deep learning.

My comments following pertain to upper-division and first-year graduate courses in basic engineering. Such courses are difficult but cover well-known subject matter. Consequently, my problem is to help the students learn the material, to be an effective catalyst who speeds up their learning. Engineering students are highly motivated; those who are not jumped out of the frying pan a long time ago.

The importance of meticulous preparation cannot be overemphasized: not only in planning the course, but in laying out the details in each and every lecture. Even if I have taught a course several times, each lecture must be carefully prepared. Indeed, I want to teach each lecture as I see the material today: recent developments suggest new illustrations, new examples, etc.; they help to keep the course alive.

Basic concepts must carefully be stated and illustrated, and their limitations explicitly stated. Consistent and explicitly defined notations and sign conventions are crucial to avoid chaos.

The overhead projector is a wonderful instrument for complicated figures, tables, definitions, and theorems, and the use of color is very effective for emphasis, for separating issues, etc. (of course, the students have copies of the overheads). The time saved should be used for intuitive comments, illustrations and examples.

All derivations must be done step by step on the board: first, it slows you down; second, it allows you to verbalize the justification of each equation, each argument and each manipulation.

At the start of the course, tell the students that you are fallible and that if they are uncomfortable with something you have said or written, they should ask a question. In my opinion, there are no stupid questions, only puzzled students.

At the start of every lecture, write down a "menu" listing the topics to be covered and, as appropriate, precise references to textbooks or papers.