From Academic Kids
In lay terms, an invention is a novel device, material, or technique.
One question that society often asks is, "What conditions lead to the development of an invention?" There are two main opposing viewpoints on this. One school of thought argues that a lack of resources leads people to invent (popularized in the phrase "necessity is the mother of invention"), while the other school of thought argues, conversely, that only an excess of resources will result in inventions.
Castles in the air (or castles in Spain) are creative ideas that do not reach fruition due to practical considerations. The history of invention is full of such castles, as inventions are not necessarily invented in the order that is most useful. For example, the design of the parachute was worked out before the invention of powered flight. Other inventions simply solve problems for which there is no economic incentive to provide a solution.
Following the terminology of political economist Joseph Schumpeter, an invention differs from an innovation. While an invention is merely theoretical (even though it might have been filed with the Patent Office), an innovation is an invention that has been put into practice. However, this conflicts with the theory of social anthropologists and other social sciences researchers. In social sciences, an innovation is anything new to a culture. The innovation does not need to have been adopted. The theory for adoption (or non-adoption) of an innovation is called diffusion of innovations. This theory, first put forth by Everett Rogers, considers the likelihood that an innovation will ever be adopted and the taxonomy of persons likely to adopt it or spur its adoption. Gabriel Tarde also dealt with the adoption of innovations in his Laws of Imitation.
List of Inventors and Inventions