Science is the methodical study of the natural world, collecting physical evidence and creating a body of provisional explanations for observed phenomena. It is often divided into specialized fields such as chemistry, biology or physics. Science, by its nature, is constantly evolving, which makes it possible to learn new things about the natural world.
However, many scientists engage in work that can be considered engineering, such as testing hypotheses or designing new technologies for purposes of advancing scientific research. Indeed, technology provides the eyes and ears (and some of the muscle) of science by enabling new lines of inquiry that might not be feasible without it. For example, new instruments are continually being developed through technology that help scientists advance research on weather systems, gene structure, demographic patterns and more.
While a deep understanding of scientific principles often precedes engineering, in other cases, the goal of developing a particular technology drives its invention. One notable example is the development of cell phones, for which the vision was that any person would be able to speak to any other through a handheld device. To achieve this, engineers had to overcome a host of constraints that included limited basic scientific knowledge of electromagnetic waves and high-density integrated circuitry.
The goal orientation of engineering is also reflected in the way that engineers study the world. For example, mechanical engineers divide their research into statics (or the study of forces on a mechanism) and kinematics (the study of how motion changes a mechanism's position and velocities). A similar approach is taken by materials scientists, who seek to understand such factors as support loads, stiffness and brittleness.