läbipaistmatutest

Läbipaistmatutest is a term of Estonian origin that translates to "opaque" in English. In physics and optics, an opaque material is one that does not transmit light. Instead, light striking an opaque object is either reflected or absorbed. This is in contrast to transparent materials, which allow light to pass through them, and translucent materials, which scatter light as it passes through.

The property of being opaque is determined by the material's composition and structure. Light can interact with matter in several ways, including absorption, reflection, and transmission. In opaque substances, the photons of light are absorbed by the electrons within the material. These electrons then return to their ground state, often releasing energy as heat. Some light may also be reflected from the surface of the opaque object.

Examples of opaque materials are abundant in everyday life. Wood, stone, metals, and most plastics are opaque. This property is crucial in many applications, such as in construction where opaque materials are used for walls to block light and provide privacy, or in the design of clothing to prevent sunlight from passing through. The degree of opacity can vary significantly between different materials, ranging from substances that are only slightly opaque to those that are completely opaque and absorb almost all incident light. The study of opacity is fundamental to understanding how light interacts with the physical world and is important in fields like material science, photography, and astrophysics.