Being both a scientist and an engineer, I'd say that is as good an explanation as I've seen. I might want to modify that to "naturally-occurring stuff", but I think we all get the general idea.
GM Samaras Pueblo, CO
I guess the spectrum is continuous, so in the real world, the differences are often not sharply defined. In principle, a scientist makes discoveries that may or may not lead to anything tangible. Where an engineer applies the knowledge.
But then take someone like Claude Shannon. How would you classify him? Among other inventions and discoveries, he derived what we call Shannon's Equation (relationship between channel capacity, noise, and bandwidth), which some might say is a scientist's or a mathematician's "job," but he studied EE at U Michigan and MIT. He did a lot of theoretical work in cryptography. All for real, practical purposes, but theoretical work nevertheless.
I will take this one step further: I believe that one can consider the technician, engineer, and scientist as a spectrum.
The scientist discovers new principles, and the best scientists are extremely valuable to society in the long term, for example, the discovery of electricity and semiconductors are essential to modern life. A good scientist may create enormous value but has little day-to-day responsibility.
The engineer makes use of scientific principles and empirical knowledge to devise new solutions to problems and to create new products, and is valuable in a medium term. He has considerable responsibility and targets to meet, within timescales longer than day-to-day.
The technician produces and operates these new products, and is equally valuable in the short term, designing the detailed product and running the factory efficiently. He has
In some cases, the value of the technician is recognised - a GP or Dentist mostly carries out standard procedures, which is a technician's task, and is well paid for it. Someone running a semiconductor fab is doing a high-level technician task, which I would not wish to give to an engineer and even less to a scientist.
The scientist may make 1000% changes, that is order of magnitude; engineers may make 100% changes; the technician may make 10% changes, which may be the difference between success ad failure of the rfinery or semi fab.
Scientists study parts of the universe, creating mathematical models describing what can and cannot be done. Engineers take the scientists' models (often from multiple disciplines) and find a way to achieve the same end as if the impossible were possible.
Consider meta-materials that behave as if they had a negative index of refraction. Negative indices of refraction are impossible, but the combination of resonant units at sufficiently small scales behave as if they did, for a given frequency range, without violating that principle.