People use materials routinely and without worrying about the structure within. If the material functions reliably then there is no justification to think further. There are 9 million scientists in the world today, of whom about 300,000 are concerned with materials -- i.e., a fraction 0.00004 of the world's population. This very special minority  drives the creation of new materials by probing and manipulating the structure of materials. Structure itself is as defined over length scales that range from atoms to engineering dimensions so the subject is inherently interdisciplinary like no other.