The Mohs Hardness of Coins

The Mohs Hardness of Coins The Mohs scale of mineral hardness consists of ten different minerals, but some other common objects can also be used: these include the fingernail (hardness 2.5), a steel knife or window glass (5.5), a steel file (6.5), and a penny. The penny has always been assigned a hardness of around 3. But we have conducted tests and found this is not true. The penny has changed in composition over the years since 1909 when the first Lincoln cent was issued. Its composition was specified as 95 percent copper and 5 percent tin plus zinc, an alloy classified as bronze. Except for the wartime year of 1943, pennies were bronze from 1909 until 1962. Pennies for the following 20 years were copper and zinc, technically brass rather than bronze. And in 1982 the proportions were reversed so that pennies today are 97.5 percent zinc surrounded by a thin, thin copper shell. Our test penny was from 1927, the original bronze formula. When we tested it with a new penny, neither scratched the other, so its clear that the hardness of pennies has not changed. Our penny would not scratch calcite unless we really bore down on it, but calcite (the standard for hardness 3) scratched the penny. In the interest of science, we tested a quarter, a dime and a nickel against the penny and against calcite. The quarter and dime were slightly softer than the penny and the nickel was slightly harder, but all were scratched by calcite. We did not experiment with silver coins, however, on a wild hunch, we tested an Indian head penny from 1908 and found that it scratched all the other objects and was not scratched in turn. So with that exception, all American coins do not scratch clear calcite without a lot of effort, whereas calcite scratches them fairly easily. This gives them a hardness less than 3, that is, 2.5, while an Indian head penny has a hardness greater than 3, that is, 3.5. The Indian head penny had the same nominal composition as the Lincoln penny, with zinc and tin combined making up 5 percent, but we suspect that the older penny had a little more tin. Maybe one penny isnt a fair test. Is there any reason to carry a penny around when the fingernail also is hardness 2.5? I think there are two: One, you may have soft nails; and two, you may prefer to scratch a penny rather than your nails. But the practical geologist should carry a nickel instead because in an emergency it can feed a parking meter.

Answers to Questions About Writing Fiction

Answers to Questions About Writing Fiction Answers to Questions About Writing Fiction Answers to Questions About Writing Fiction By Mark Nichol Here are three questions from DailyWritingTips.com readers about aspects of fiction writing, each followed by my response. 1. When it comes to fiction dialogue, do any grammatical rules apply? Generally, dialogue in fiction should be consistent with the speech patterns and habits of the individual characters; that’s one way to convey their personalities, and such idiosyncrasy provides a note of authenticity. Search DailyWritingTips.com for â€Å"dialogue† to find numerous posts on the topic. 2. I have always thought that when writing dialogue and a character’s speech runs into multiple paragraphs, each paragraph should begin and end with quotation marks. However, recently I’ve seen it published where the first paragraph ends with no quotes but the second one begins and ends with them. Which is the correct way? The way you’ve seen it recently is standard: â€Å"First, second, and all other paragraphs except for the final one. â€Å"Final paragraph.† All paragraphs but the final one are left open because including a close quotation mark might lead a reader to believe that the quotation is final and that the next paragraph consists of a different character’s speech. The lack of a closing mark at the end of one paragraph and the use of an opening mark in the subsequent paragraph signals that the speech is continuing. It’s a good idea, however, to toss in an attribution or some stage business to identify the speaker now and then in an extended speech or in a conversation involving more than two speakers. 3. Why is it a crime to use a clichà © in a novel? We all use clichà ©s in talking with people, so why the big no-no when writing? In social situations and other informal environments, â€Å"lazy† language is acceptable it’s a lot of work to keep up careful discourse. The same is true with casual writing. But novels should be written with the utmost care, even if the tone is colloquial, with language that is as fresh and original as possible. Occasional idioms are acceptable, but strive to find your own way of expressing a thought or conjuring an image. Ultimately, the choice is up to you, but reader response (or lack thereof) may change your mind. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Fiction Writing category, check our popular posts, or choose a related post below:Bare or Bear With Me?15 Words for Household Rooms, and Their Synonyms25 Idioms with Clean