DEVELOPMENT OF THE PERIODIC TABLE Although Dmitri Mendeleev is often considered the "father" of the periodic table‚ the work of many scientists contributed to its present form. Elements such as gold‚ silver‚ tin‚ copper‚ lead and mercury have been known since earliest times. In 1649 the first scientific discovery of an element occurred. Hennig Brand‚ a German chemist‚ treated urine to a series of processes that resulted in the production of the element phosphorus. Over the next 200 years
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HISTORY OF THE PERIODIC TABLE How did the periodic table develop? Since a very long time‚ elements such as gold‚ silver‚ tin‚ copper‚ lead and mercury have been known. But the concept of elements have largely be changed since then. Many scientists did research and new scientific discoveries were found. The progress of science never ends. Lavoisier In 1789‚ French chemist Antoine Laurent Lavoisier discovered that an element is a fundamental substance that could not be broken down by
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Pivot joint: A rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament . The bone rotates within this ring. Since the rotation is around a single axis‚ pivot joints are functionally classified as a uniaxial diarthrosis type of joint. An example of a pivot joint is the atlantoaxial joint‚ found between the C1 (atlas) and C2 (axis) vertebrae. Here‚ the upward projecting dens of the axis articulates with the inner aspect
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If one didn’t have the ability to joint two pieces of wood together in a solid fashion‚ all woodworking pieces would be sculptures‚ carved out of a single piece of wood. However‚ with the many varied types of wood joinery‚ a woodworker has a number of different joints in his arsenal from which to choose‚ based upon the project. If you master these wood joinery concepts‚ you’ll be well on your way to becoming a very accomplished woodworker. 1. Basic Butt Joint (c) 2009 Chris Baylor licensed to
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would she want joint custody and says “No‚ he is unfit to raise a child.” .Everyone knows what joint custody is. It’s when the custody of a child is awarded to both parents by the court. But would you want an abusive father or a drinking mother to have joint custody of your innocent child? Some people think joint custody is good for the child just because they get to see and spend time with both parents. Well that’s not always the case. Its is more likely that parents will agree with joint custody because
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Introduction The knee is one of the largest and most complex joints in the body. The knee joins the femur to the tibia. The smaller bone that runs alongside the tibia is the fibula. The patella‚ also known as the knee-cap‚ is another one that makes up the knee joint. I decided to discuss this joint structure because of reoccurring knee injuries. The Knee Joint The knee joint is formed by the articulation of the distal end of the femur and the proximal end of the tibia. The fibula
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A periodic inventory system is an accounting method in which the cost of goods sold is determined periodically‚ usually annually and typically not more frequently than quarterly. The disadvantage is the systems inability to continuously update inventory levelsThe periodic inventory system is most useful for smaller businesses that maintain minimal amounts of inventory. For them‚ a physical inventory count is easy to complete‚ and they can estimate cost of goods sold figures for interim periods. However
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BY JACOB WOODS 12G Synovial Joints Synovial joints are characterised by a layer of synovial fluid surrounding the articulating surfaces. This helps to lubricate the cartilage therefore reducing the friction between the joints. The synovial capsule stores the fluid‚ meaning it can lubricate the joint quickly. There are 5 types of synovial joint. They are as follows. Ball and socket joint Spheroidal joints to give them their technical name are joints that include two articular surfaces; a ball
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A joint is defined as a fracture in a rock between the sides of which there is no observable relative movement. They are present is most consolidated rocks of igneous‚ metamorphic and sedimentary origin. Joints may form as a result of either diastrophism or contraction. Description: (i) A series of parallel joints is called a ’joint set’. (ii) Two or more joint sets intersecting each other produce a ’joint system’. (iii) Two sets of joints nearly at right angles to one another‚ produced by the
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Types of joints: Ball-and-socket joint: Consists of a bone with a globular or slightly egg-shaped head that articulates with the cup-shaped cavity of another bone. Such a joint allows a wider range of motion than does any other kind‚ permitting movements in all planes‚ as well as rotational movement around a central axis. The hip and shoulder contain joints of this type. Condyloid joint: The ovoid condyle of one bone fits into the elliptical cavity of another bone‚ as in the joints between the
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