Plastic in the context of "Lens (optics)"

Drawing is a visual art that uses an instrument to mark paper or another two-dimensional surface, or a digital representation of such. Traditionally, the instruments used to create a drawing include pencils, crayons, and ink pens, sometimes in combination. More modern tools include computer styluses with mice and graphics tablets and gamepads in VR drawing software.

A drawing instrument releases a small amount of material onto a surface, leaving a visible mark. There are many drawing instruments such as pen, pencils, pastel, crayons, markers, color pencils, water color, and more. The most common support for drawing is paper, although other materials, such as cardboard, vellum, wood, plastic, leather, canvas, and board, have been used. Temporary drawings may be made on a blackboard or whiteboard. Drawing has been a popular and fundamental means of public expression throughout human history. It is one of the simplest and most efficient means of communicating ideas. The wide availability of drawing instruments makes drawing one of the most common artistic activities.

A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis. Lenses are made from materials such as glass or plastic and are ground, polished, or molded to the required shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing. Devices that similarly focus or disperse waves and radiation other than visible light are also called "lenses", such as microwave lenses, electron lenses, acoustic lenses, or explosive lenses.

Lenses are used in various imaging devices such as telescopes, binoculars, and cameras. They are also used as visual aids in glasses to correct defects of vision such as myopia and hypermetropia.

Molding (American English) or moulding (British and Commonwealth English; see spelling differences) is the process of manufacturing by shaping liquid or pliable raw material using a rigid frame called a mold or matrix. This itself may have been made using a pattern or model of the final object.

A mold or mould is a hollowed-out block that is filled with a liquid or pliable material such as plastic, glass, metal, or ceramic raw material. The liquid hardens or sets inside the mold, adopting its shape. A mold is a counterpart to a cast. The very common bi-valve molding process uses two molds, one for each half of the object.

The petroleum industry, also known as the oil industry, includes the global processes of exploration, extraction, refining, transportation (often by oil tankers and pipelines), and marketing of petroleum products. The largest volume products of the industry are fuel oil and gasoline (petrol). Petroleum is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, synthetic fragrances, and plastics. The industry is usually divided into three major components: upstream, midstream, and downstream. Upstream regards exploration and extraction of crude oil, midstream encompasses transportation and storage of it, and downstream concerns refining crude oil into various end products.

Petroleum is vital to many industries, and is necessary for the maintenance of industrial civilization in its current configuration, making it a critical concern for many nations. Oil accounts for a large percentage of the world's energy consumption, ranging from a low of 32% for Europe and Asia, to a high of 53% for the Middle East.

A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials/Intermediate goods that are feedstock for future finished products. As feedstock, the term connotes these materials are bottleneck assets and are required to produce other products.

The term raw material denotes materials in unprocessed or minimally processed states such as raw latex, crude oil, cotton, coal, raw biomass, iron ore, plastic, air, logs, and water. The term secondary raw material denotes waste material which has been recycled and injected back into use as productive material.

Furniture refers to objects intended to support various human activities such as seating (e.g., stools, chairs, and sofas), eating (tables), storing items, working, and sleeping (e.g., beds and hammocks). Furniture is also used to hold objects at a convenient height for work (as horizontal surfaces above the ground, such as tables and desks), or to store things (e.g., cupboards, shelves, and drawers). Furniture can be a product of design and can be considered a form of decorative art. In addition to furniture's functional role, it can serve a symbolic or religious purpose. It can be made from a vast multitude of materials, including metal, plastic, and wood. Furniture can be made using a variety of woodworking joints which often reflects the local culture.

People have been using natural objects, such as tree stumps, rocks and moss, as furniture since the beginning of human civilization and continues today in some households/campsites. Archaeological research shows that from around 30,000 years ago, people started to construct and carve their own furniture, using wood, stone, and animal bones. Early furniture from this period is known from artwork such as a Venus figurine found in Russia, depicting the goddess on a throne. The first surviving extant furniture is in the homes of Skara Brae in Scotland, and includes cupboards, dressers and beds all constructed from stone. Complex construction techniques such as joinery began in the early dynastic period of ancient Egypt. This era saw constructed wooden pieces, including stools and tables, sometimes decorated with valuable metals or ivory. The evolution of furniture design continued in ancient Greece and ancient Rome, with thrones being commonplace as well as the klinai, multipurpose couches used for relaxing, eating, and sleeping. The furniture of the Middle Ages was usually heavy, oak, and ornamented. Furniture design expanded during the Italian Renaissance of the fourteenth and fifteenth century. The seventeenth century, in both Southern and Northern Europe, was characterized by opulent, often gilded Baroque designs. The nineteenth century is usually defined by revival styles. The first three-quarters of the twentieth century are often seen as the march towards Modernism. One unique outgrowth of post-modern furniture design is a return to natural shapes and textures.

A jar is a rigid, cylindrical, or slightly conical container, typically made of glass, ceramic, or plastic, with a wide mouth or opening that can be closed with a lid, screw cap, lug cap, cork stopper, roll-on cap, crimp-on cap, press-on cap, plastic shrink, heat-sealed lidding film, an inner seal, a tamper-evident band, or other suitable means. The English word "jar" originates from the Arabic word jarra, which means an earthen pot or vessel.

A bracelet is an article of jewellery that is worn around the wrist. Bracelets may serve different uses, such as being worn as an ornament. When worn as ornaments, bracelets may have a supportive function to hold other items of decoration, such as charms. Medical and identity information can be marked on some bracelets, such as allergy bracelets, hospital patient-identification tags, and bracelet tags for newborn babies. Bracelets may be worn to signify a certain phenomenon, such as breast cancer awareness, for religious/cultural purposes or as a sign of LGBTQ pride.

If a bracelet is a single, inflexible loop, it is often called a bangle. When it is worn around the ankle it is called an ankle bracelet or anklet. A boot bracelet is used to decorate boots. Bracelets can be manufactured from metal, leather, cloth, plastic, bead or other materials, and jewellery bracelets sometimes contain jewels, rocks, wood, shells, crystals, metal, or plastic hoops, pearls and many more materials.

Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plastics, and other materials. The atoms/molecules in the sintered material diffuse across the boundaries of the particles, fusing the particles together and creating a solid piece.

Since the sintering temperature does not have to reach the melting point of the material, sintering is often chosen as the shaping process for materials with extremely high melting points, such as tungsten and molybdenum. The study of sintering in metallurgical powder-related processes is known as powder metallurgy.