The document provides examples of descriptions of inventions and discoveries. It describes Whitcomb Judson's invention of the zipper in 1893. It also summarizes the discovery of radioactivity by Antoine Henri Becquerel in 1896, when he discovered that uranium salts emitted invisible and penetrating rays capable of exposing photographic plates even in the dark. Additionally, it discusses the discovery of DNA in the early 1950s by Francis Crick and James Watson at Cambridge University and Maurice Wilkins and Rosalind Franklin at King's College in London.

3. EXAMPLE 2 The Discovery of Radioactivity It's been 100 years since the discovery of radioactivity. Happy 100th Birthday! This section will describe the surprise discovery of radiation and the significant contributions of several other scientists. How exciting it must have been for them to be on the forefront of such new and exciting research! Little did they know how much their discoveries would benefit mankind 100 years in the future.

7. Did you know this?? In 1903, Becquerel and the Curie together received the Nobel Prize in physics. This award was for their discovery of radioactivity and their other contributions in this area. Marie Curie received a second Nobel Prize in 1911 for the discovery of polonium and radium. She was the first person to win two Nobel Prizes. Did you know that the Curie's had a word named after them? That's right! The curie is a basic unit of measurement for describing radioactivity. http://www.chem.duke.edu/~jds/cruise_chem/nuclear/discovery.html

8. EXAMPLE 3 The Discovery of DNA In the early 1950s, the race to discover DNA was on. At Cambridge University, graduate student Francis Crick and research fellow James Watson (b. 1928) had become interested, impressed especially by Pauling's work. Meanwhile at King's College in London, Maurice Wilkins (b. 1916) and Rosalind Franklin were also studying DNA. The Cambridge team's approach was to make physical models to narrow down the possibilities and eventually create an accurate picture of the molecule. The King's team took an experimental approach, looking particularly at x-ray diffraction images of DNA. In 1951, Watson attended a lecture by Franklin on her work to date. She had found that DNA can exist in two forms, depending on the relative humidity in the surrounding air. This had helped her deduce that the phosphate part of the molecule was on the outside. Watson returned to Cambridge with a rather muddy recollection of the facts Franklin had presented, though clearly critical of her lecture style and personal appearance. Based on this information, Watson and Crick made a failed model. It caused the head of their unit to tell them to stop DNA research. But the subject just kept coming up. (…)

9. Example 4 The discovery of Lithium The petalite and spodumene (minerals containing lithium) were discovered by the Brazilian scientist José Bonifácio de Andrada e Sìlva at the end of the 18th century while visiting Sweden. Lithium was then discovered by Swedish scientist Johan August Arfvedson in 1817 during an analysis of petalite ore, an ore now recognised to be LiAl(Si2O5)2, taken from a Swedish island. Arfvedson subsequently discovered lithium in the minerals spodumene and lepidolite. He named new element as a lithium (from Greek word lithos meaning stone. The first isolation of elemental lithium was achieved later in 1818 by Sir Humphrey Davy by the electrolysis of Li2O. In 1855, Bunsen and Mattiessen isolated larger quantities of the metal by electrolysis of lithium chloride. Lithium metal is prepared by the electrolysis of a fused mixture of lithium chloride and potassium chloride in a cell at a temperature of about 400 °C recently.

11. Description Lithium has a silvery appearance but quickly becomes covered by a film of black oxide when exposed to air. It is usually stored immersed in an inert oil. Lithium is the lightest of all metals. Reacts slowly with oxygen and water. In solution, a lithium will give an intense carmine-red flame test color, the color somewhat resembling that of the strontium flame but deeper. In very small quantities it is visible using a diffraction spectroscope. The lithium minerals, which are either silicates or phosphates, do not become alkaline after ignition.