Engineering vs. Science

I’ve been an engineering professor for a long time (28 years now, but I still feel like a grad student).  In my current department, most of the faculty were trained as scientists, not engineers, and the differences are sometimes striking.  The public always lumps together science and engineering, and the education establishment even more so, lumping Science, Technology, Engineering, and Math together as STEM fields. But there is a difference, and it is sometimes important.

So, what is the difference between science and engineering? and does it really matter to anyone?

The difference between science and engineering is not so much in what you need to know to do them, but in what sort of questions you ask.

Science is mainly about “why?” questions: why is the sky blue? why can stem cells keep proliferating, while differentiated cells do not? The focus is on Discovery—studying phenomena and building models that explain them and enable accurate predictions about so far unobserved phenomena.  Acquiring new knowledge and understanding is the main goal.

Engineering is mainly about “how?” questions: how can I sequence DNA cheaper and more accurately? how can I kill cancer cells without killing stem cells? how can I make a cell phone that people will want to buy, even though they have  perfectly good phones in their pockets already?  The focus is on Invention—making new things or processes, on solving real-world problems, rather than on acquiring knowledge.

Take a look some time at what projects win at local and state “science” fairs.  The lists are almost always dominated by engineering projects—ones that try to solve a real-world problem using already well-known science.  The fields can be quite diverse, though lately health and environment applications have been the most successful.  At least the Intel International Science and Engineering Fair has an honest title including engineering, unlike most of the state science fairs.

Chicken or egg?

People have been taught since elementary school that science comes first, and that engineering is the application of science.  But this is a gross oversimplification of the real situation, which involves a cycle:  a phenomenon is discovered (science), an application for it is found (engineering), the application allows new things to be discovered (science), which in turn allows new applications, leading to new discoveries, … .

In the old days, this cycle was often quite slow, with generations between the discovery of a phenomenon and its application.  Nowadays, the cycle is often much shorter, with the application coming almost simultaneously with the discovery of the phenomenon. Consider, for example, RNA interference (RNAi).  The phenomenon of anti-sense RNA reducing the expression of genes in various organisms was first discovered in the  early 1980s (or perhaps late 1970s, I’ve not traced the original papers).  It was almost immediately used to control expression in genetic experiments.  A lot of both science (how does RNA control expression of genes?) and engineering (how can we reliably use RNAi to knock-down expression of genes we wish to control?) has been done since, and RNAi has become a standard tool for biotechnology, particularly for studying multi-celled creatures, where knocking out genes can be expensive or impossible.

Nowadays, the important advances in molecular biology are usually the result of a new tool becoming available (like high-throughput sequencing), so that the field is driven forward mostly by the engineering advances.  As the new tool becomes available, thousands of scientists start using it, and some interesting discoveries are made (plus a whole lot of rather boring minor ones—the trouble is, we don’t know in advance which ones will be important and interesting).

Who cares?

A single individual can do both science and engineering, discovering phenomena and applying them. So what is the point of making a distinction?

There is a distinct difference in the training one should give a student who is planning to be a scientist and one who is planning to be an engineer.  Sure, the basics are the same at the beginning (basic science, math, lab technique, computer programming, statistics, and so forth), but the engineer has to be taught how to design and debug, while the scientist has to be taught how to question dogma and discover new ideas.  These are not the same skills at all and both need substantial practice before people are competent at them.

For scientists, the tradition has been to devote the undergraduate years to acquiring basic knowledge, but not to practice being a scientist at all.  As a result it takes 5–7 years of grad school (and often several years of post doctoral training) to turn science undergrads into scientists. For engineers, the tradition has been to do 2–3 years of basic training, followed by 2–3 years of project work of gradually increasing complexity, culminating in either a B.S. or an M.S. degree.

The shorter training time for engineers means that it must be much more focused—you can’t hope that the students will pick up skills they need gradually as a by-product of years of doing something else (the way that scientists are trained). Instead, the specific design skills and group management skills need to be explicitly taught and practiced while the students are still undergrads.  This has a lot of consequences for curriculum design, as almost all junior and senior courses have to include design practice, and there needs to be at least one big project (preferably one too big for a single engineer to handle).  Explaining these curricular needs to faculty trained as scientists can be difficult—they want to leave all that to the grad curriculum or one-on-one training of postdocs.