Passage 1
P.>fkO1\ As the horizons of science have expanded, two main groups of scientists have emerged. One is the pure scientist; the other, the applied scientist.
)$p36dWl The pure or theoretical scientist does original research in order to understand the basic laws of nature that govern our world. The applied scientist adapts this knowledge to practical problems. Neither is more important than the other, however, for the two groups are very much related. Sometimes, however, the applied scientist finds the "problem" for the theoretical scientist to work on. Let's take a particular problem of the aircraft industry: heat-resistant metals. Many of the metals and alloys which perform satisfactorily in a car cannot be used in a jet-propelled plane. New alloys must be used, because the jet engine operates at a much higher temperature than an automobile engine. The turbine wheel in a turbojet must withstand temperatures as high as 1,600 degrees Fahrenheit, so aircraft designers had to turn to the research metallurgist for the development of metals and alloys that would do the job in jet-propelled planes.
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