diameter reading
11Lathe — A lathe (pronEng|ˈleɪð) is a machine tool which spins a block of material to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has… …
12Halfpenny (British pre-decimal coin) — The British halfpenny coin was worth 1/480th of a pound sterling. At first in its 700 year history it was made from silver but as the value of the pound declined, the coin was made from base metals. It was finally abandoned in 1969 as part of the …
13Neon sign — …
14Crossrail — For other uses, see Crossrail (disambiguation). Crossrail Crossrail logo Overview Type Commuter rail, Suburban rail …
15mathematics — /math euh mat iks/, n. 1. (used with a sing. v.) the systematic treatment of magnitude, relationships between figures and forms, and relations between quantities expressed symbolically. 2. (used with a sing. or pl. v.) mathematical procedures,… …
16eye, human — ▪ anatomy Introduction specialized sense organ capable of receiving visual images, which are then carried to the brain. Anatomy of the visual apparatus Structures auxiliary to the eye The orbit The eye is protected from mechanical injury… …
17Impact crater — The prominent impact crater Tycho on the Moon. In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body. In most common usage,… …
18Depth of field — The area within the depth of field appears sharp, while the areas in front of and beyond the depth of field appear blurry …
19photography, technology of — Introduction equipment, techniques, and processes used in the production of photographs. The most widely used photographic process is the black and white negative–positive system (Figure 1 >). In the camera the lens projects an image of… …
20History of the telescope — The earliest known working telescopes appeared in 1608 and are credited to Hans Lippershey and Zacharias Janssen, spectacle makers in Middelburg, and Jacob Metius of Alkmaar. The design of these early refracting telescopes consisted of a convex… …
