Science is a particular kind of pursuit of a particular kind of knowledge. Not many people stop to think what this might mean -- I encourage the reader to do so now.
"The pursuit of knowledge" in science's case comes with some burdens. The pursued knowledge is about nature, in a simple, revealing, principled and fundamental sense. This is the goal of "theory". It is in contrast to, or complement with, "the details". Of course, details inspire the pursuit of scientific questions, but "knowing details" is not the kind of knowledge science pursues. Certain details are pursued, surely, as part of the process of asking questions which can lead to both significant experiments and better theories. Scientific knowledge, or a theory (always tentatively held) usually comes in the form of some typically non-intuitive, interesting principle, or model, one that has held up pretty well (or at least better than others) during prediction, observation and experiment, and which offers insight into how the world works: the world outside our senses and intuitions. Examples of scientific insights that have no attached equations (i.e. models):
- "the air" is not empty, but is instead full of all kinds of stuff
- gravity is a property of all 'matter'
- there is no "matter & energy"... just energy
- we have no contact-mechanical explanation for gravity
Engineering, by contrast, is "building something" for "some purpose". Now, a lot of engineering is done to help in the pursuit of science. And a lot of engineering is only possible because of scientific results. But they are not the same thing.
A nice example came up, in conversation the other day with a chemical engineer ... when he needs to achieve some result, and one potential chemical reaction doesn't do the trick, he can't stop and ask "what's going on here"? Because that would be science. He has a job to do, so he just tries another process, and another, until the results are achieved. That's engineering.
Some confusion may arise because both are highly technical human activities, and so, from almost any perspective, they have more in common than in distinction. For example, there are two processes that are common to both science (uncovering nature) and engineering (getting stuff done):