How to Write a Summary of an Article? The social issues and problems arising in Madang town are always in relation to rising settlers e. There are many factors of that can hinder tourism growth such as law and order problem, political unrest and the economy crisis of the country.
Chemistry in its element: End promo Chris Smith Hello! Welcome to Chemistry in its element. This week, we're demystifying the element behind the photograph and to cross your cognitive palm with silver, here's Victoria Gill.
Victoria Gill Its lustre shine has been coveted since ancient times. It's not just rare or precious, as its more expensive cousin, gold, but there is evidence from as early as BC that humans extracted silver from naturally occurring silver sulphide deposits in rocks to make coins and jewellery.
These coins actually form the basis for the economies of some ancient Mediterranean civilizations. It's a soft and pliable metal with a relatively low melting point and that means it can be hammered and moulded into shape, so the same metal that was used to make money that was gradually outdated could also be transformed into vases, platters, cutlery and goblets; tableware that has created displays of household wealth through the centuries.
But a gleaming collection of silverware isn't easy to maintain. The metal reacts with sulphur in the air, rapidly forming a dull, dark silver sulphide tarnish that has to be polished off. So it's a high maintenance element; another reason why it has always been outshone by gold.
But the same chemical properties that tarnished its image let it to make another mark in history, by allowing history itself to be recorded in the photograph.
Ina German physicist called Johann Heinrich Schulze found that a paste of chalk and silver nitrate salt was blackened by light. He used stencils to produce black images with the paste. This reaction, the dawn of photography, was all thanks to the fact that silver salts are sensitive to light.
A photon of light hitting the negative nitrate anion frees an electron, which ultimately combines with the positive silver ions to make neutral silver metal, darkening the surface of the material.
When inHenry Talbot discovered an additional chemical twist, that is so called latent silver image, that had been briefly exposed onto a layer of silver iodide could be revealed using gallic acid, the effect was seen as magical, a devilish art.
But this mystical development of an invisible picture was a simple reduction reaction; the gallic acid helping to reduce photosensitized silver ions into silver metal. Hollywood could never have existed without the chemical reaction that gave celluloid film its ability to capture the stars and bring them to the aptly dubbed silver screen.
Digital photography may now have eclipsed the silver image, but the metal's ability to conduct has given it an important role in the digital age. Silver is used on circuit boards and in batteries, where the conduction speed is needed that copper for example, can't quite deliver.
Even its most outdated properties are making resurgence. With new antibiotics running thin, a few researchers are returning to silver as a coating to keep the bugs at bay. Silver metal is toxic to nasty bacteria, but not to us and there is even a tiny amount of it in our bodies, but that's yet to give up the secret of why it's there.
For me, rather superficially, it's always been gold's subtler, prettier counterpart. Chris Smith Victoria Gill uncovering the secrets of the element that gave us the silver screen.
Next time on Chemistry in its element, John Emsley introduces a chemical that's mostly fallen from favour, perhaps with good reason.
Praise for Barbara Ehrenreich: “Impassioned, fascinating, profoundly significant, and wildly entertaining.” —Francine Prose, O, The Oprah Magazine, on Nickel and Dimed “One of today’s most original writers.”. This essay has been submitted by a law student. This is not an example of the work written by our professional essay writers. Background Information Of Gems And Jewellery. The EU adopted a measure prohibiting using nickel as a mixture over %. In the EU, manufacturers and importers of jewellery that contain nickel are under. Example Analysis-Evaluation Essays #1 Webpublished with Student Permission Online Handout, WR , Winter One strength Decter brought to her essay was the background information on herself. Before the essays starts, an important fact is mentioned. In the essay Nickel outlines the causes and effects that bigotry has on our children.
John Emsley This trouble-making element has attacked the ozone layer, and its mere presence has caused entire reservoirs to be drained. Chris Smith And you can hear John Emsley telling the story of the brown element, bromine, on next week's Chemistry in its element.Praise for Barbara Ehrenreich: “Impassioned, fascinating, profoundly significant, and wildly entertaining.” —Francine Prose, O, The Oprah Magazine, on Nickel and Dimed.
Background information can also include summaries of important, relevant research studies. This is particularly important if there is an essential or groundbreaking study about the research problem or a key study that refutes or supports your thesis.
Nickel is used in batteries, including rechargeable nickel-cadmium batteries and nickel-metal hydride batteries used in hybrid vehicles. Nickel has a long history of being used in coins. The US five-cent piece (known as a ‘nickel’) is 25% nickel and 75% copper.
Example Analysis-Evaluation Essays #1 Webpublished with Student Permission Online Handout, WR , Winter One strength Decter brought to her essay was the background information on herself.
Before the essays starts, an important fact is mentioned. In the essay Nickel outlines the causes and effects that bigotry has on our children. * Background Information:Acid rain is caused by air pollution when fossil fuels such as coal, oil or natural gas is burnt and when smoke is emitted from industries into the air.
Praise for Barbara Ehrenreich: “Impassioned, fascinating, profoundly significant, and wildly entertaining.” —Francine Prose, O, The Oprah Magazine, on Nickel and Dimed “One of today’s most original writers.”.