Ernest Rutherford Discovers the Structure of an Atom

• Ernest Rutherford Discovers the Structure of an Atom. 1911

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  Ernest Rutherford in academic garb. Courtesy Edgar Fahs Smith Memorial Collection, Department of Special Collections, University of Pennsylvania Library.

  A consummate experimentalist, Ernest Rutherford (1871–1937) was responsible for a remarkable series of discoveries in the fields of radioactivity and nuclear physics. He discovered alpha and beta rays, set forth the laws of radioactive decay, and identified alpha particles as helium nuclei. Most important, he postulated the nuclear structure of the atom: experiments done in Rutherford's laboratory showed that when alpha particles are fired into gas atoms, a few are violently deflected, which implies a dense, positively charged central region containing most of the atomic mass.

  Born on a farm in New Zealand, the fourth of 12 children, Rutherford completed a degree at the University of New Zealand and began teaching unruly schoolboys. He was released from this task by a scholarship to Cambridge University, where he became J. J. Thomson's first graduate student at the Cavendish Laboratory. There he began experimenting with the transmission of radio waves, went on to join Thomson's ongoing investigation of the conduction of electricity through gases, and then turned to the field of radioactivity just opened up by Henri Becquerel and Pierre and Marie Curie.

  

  Rutherford on the New Zealand 100-dollar banknote.

  Throughout his career Rutherford displayed his ability to work creatively with associates, some of whom were already established at the institutions to which he was appointed and others of whom he attracted as doctoral or postgraduate students. At McGill University in Montreal, his first appointment, he worked with Frederick Soddy on radioactive decay. At Manchester University he collaborated with Hans Geiger (of Geiger counter fame), Niels Bohr (whose model of atomic structure succeeded Rutherford's), and H. G. J. Moseley (who obtained experimental evidence for atomic numbers). During World War I, this Manchester research group was largely dispersed, and Rutherford turned to solving problems connected with submarine detection. After the war he succeeded J. J. Thomson in the Cavendish Professorship at Cambridge and again gathered a vigorous research group, including James Chadwick, the discoverer of the neutron.

  Like Thomson, Rutherford garnered many honors. He received the Nobel Prize in chemistry for 1908; he was made a knight, then a peer with a seat in the House of Lords; and for the ultimate honor he was buried in Westminster Abbey.

   

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Boy Scouts Established in . 1907

Scouting, also known as the Scout Movement, is a worldwide youth movement with the stated aim of supporting young people in their physical, mental and spiritual development, that they may play constructive roles in society.

Scouting began in 1907 when Robert Baden-Powell, Lieutenant General in the British Army, held the first

 Scouting encampment at Brownsea Island inEngland. Baden-Powell wrote the principles of Scouting in Scouting for Boys (London, 1908), based on his earlier military books, with influence and support of Frederick Russell Burnham (Chief of Scouts in British Africa), Ernest Thompson Seton of the Woodcraft Indians, William Alexander Smith of the Boys' Brigade, and his publisher Pearson. During the first half of the 20th century, the movement grew to encompass three major age groups each for boys (Cub Scout, Boy Scout, Rover Scout) and, in 1910, a new organization, Girl Guides, was created for girls (Brownie Guide, Girl Guide and Girl Scout, Ranger Guide).

The movement employs the Scout method, a program of informal education with an emphasis on practical outdoor activities, including camping, woodcraft,aquatics, hiking, backpacking, and sports. Another widely recognized movement characteristic is the Scout uniform, by intent hiding all differences of social standing in a country and making for equality, with neckerchief and campaign hat or comparable headwear. Distinctive uniform insignia include the fleur-de-lis and the trefoil, as well as merit badges and other patches.

Secondary badge holder                   Uniform of a scout.

Activities badge

In 2011, Scouting and Guiding together had over 41 million members worldwide. The two largest umbrella organizations are the World Organization of the Scout Movement (WOSM), for boys-only and co-educational organizations, and the World Association of Girl Guides and Girl Scouts (WAGGGS), primarily for girls-only organizations but also accepting co-educational organizations. The year 2007 marked the centenary of Scouting world wide, and member organizations planned events to celebrate the occasion.

INVENTION OF PLASTICS,

Thermoplastic Moulding

The First Man-Made Plastic - Parkesine

The first man-made plastic was created by Alexander Parkes who publicly demonstrated it at the 1862 Great International Exhibition in London. The material called Parkesine was an organic material derived from cellulose that once heated could be molded, and retained its shape when cooled.

Celluloid

Celluloid is derived from cellulose and alcoholized camphor. John Wesley Hyatt invented celluloid as a substitute for the ivory in billiard balls in 1868. He first tried using collodion a natural substance, after spilling a bottle of it and discovering that the material dried into a tough and flexible film. However, the material was not strong enough to be used as a billiard ball, until the addition of camphor, a derivative of the laurel tree. The new celluloid could be molded with heat and pressure into a durable shape.

Besides billiard balls, celluloid became famous as the first flexible photographic film used for still photography and motion pictures. John Wesley Hyatt created celluloid in a strip format for movie film. By 1900, movie film was an exploding market for celluloid.

Formaldehyde Resins - Bakelite

After cellulose nitrate, formaldehyde was the next product to advance the technology of plastic. Around 1897, efforts to manufacture white chalkboards led to casein plastics (milk protein mixed with formaldehyde) Galalith and Erinoid are two early tradename examples.

In 1899, Arthur Smith received British Patent 16,275, for "phenol-formaldehyde resins for use as an ebonite substitute in electrical insulation", the first patent for processing a formaldehyde resin. However, in 1907, Leo Hendrik Baekeland improved phenol-formaldehyde reaction techniques and invented the first fully synthetic resin to become commercially successful, tradenamed Bakelite.

Timeline - Precursors

• 1839 - Natural Rubber - method of processing invented by Charles Goodyear.

• 1843 - Vulcanite - Thomas Hancock.

• 1843 - Gutta-Percha - William Montgomerie
• 1856 - Shellac - Alfred Critchlow, Samuel Peck
• 1856 - Bois Durci - Francois Charles Lepag

Timeline - Beginning of the Plastic Era with Semi Synthetics

• 1839 - Polystyrene or PS discovered - Eduard Simon
• 1862 - Parkesine - Alexander Parkes
• 1863 - Cellulose Nitrate or Celluloid - John Wesley Hyatt

• 1872 - Polyvinyl Chloride or PVC - first created by Eugen Baumann
• 1894 - Viscose Rayon - Charles Frederick Cross, Edward John Bevan

Timeline - Thermosetting Plastics and Thermoplastics

• 1908 - Cellophane ® - Jacques E. Brandenberger.

• 1909 - First true plastic Phenol-Formaldehyde tradenamed Bakelite
- Leo Hendrik Baekeland.

• 1926 - Vinyl or PVC - Walter Semon invented a plasticized PVC.
• 1927 - Cellulose Acetate
• 1933 - Polyvinylidene chloride or Saran also called PVDC - accidentally discovered by Ralph Wiley, a Dow Chemical lab worker.
• 1935 - Low-density polyethylene or LDPE - Reginald Gibson and Eric Fawcett
• 1936 - Acrylic or Polymethyl Methacrylate
• 1937 - Polyurethanes tradenamed Igamid for plastics materials and Perlon for fibers. - Otto Bayer and co-workers discovered and patented the chemistry of polyurethanes
• 1938 - Polystyrene made practical
• 1938 - Polytetrafluoroethylene or PTFE tradenamed Teflon - Roy Plunkett

• 1939 - Nylon and Neoprene
considered a replacement for silk and a synthetic rubber respectively Wallace Hume Carothers
• 1941 - Polyethylene Terephthalate or Pet - Whinfield and Dickson
• 1942 - Low Density Polyethylene
• 1942 - Unsaturated Polyester also called PET patented by John Rex Whinfield and James Tennant Dickson
• 1951 - High-density polyethylene or HDPE tradenamed Marlex - Paul Hogan and Robert Banks
• 1951 - Polypropylene or PP - Paul Hogan and Robert Banks
• 1953 - Saran Wrap introduced by Dow Chemicals.
• 1954 - Styrofoam a type of foamed polystyrene foam was invented by Ray McIntire for Dow Chemicals
• 1964 - Polyimide
• 1970 - Thermoplastic Polyester this includes trademarked Dacron, Mylar, Melinex, Teijin, and Tetoron
• 1978 - Linear Low Density Polyethylene
• 1985 - Liquid Crystal Polymers