Its all about Physics.

  Solid-state physics : Introduction: Solid-state physics is the study of rigid matter, or solids, using techniques from metallurgy, electromagnetism, crystallography, and quantum mechanics. The study of condensed matter is dominated by this field. In solid-state physics, it is investigated how the atomic-scale characteristics of solid materials translate into their large-scale characteristics. As a result, the theoretical foundation of materials science is solid-state physics. It also has direct uses, such as in semiconductor and transistor technologies.   Atoms that are tightly packed together and interact vigorously give rise to solid materials. The mechanical (such as hardness and elasticity), thermal, electrical, magnetic, and optical properties of solids are produced by these interactions. The atoms may be arranged in a regular, geometric pattern (crystalline solids, which include metals and common water ice) or randomly, depending on the material and the circumstances o...