Tin Hedgehog Experiment - Grow Tin Metal Crystals

Tin Hedgehog Experiment - Grow Tin Metal Crystals Metal crystals are intricate and beautiful. They are also surprisingly easy to grow. In this experiment, learn how to grow tin crystals that display a spiky appearance that make them look like a metal hedgehog. Tin Hedgehog Materials 0.5 M tin(II) chloride solution (SnCl2)zinc pellettest tube or vial that is larger in diameter than the zinc The rounded hedgehog shape forms around a pellet of zinc, but you can substitute any chunk of zinc metal. Since the reaction occurs at the surface of the metal, you may also use a galvanized (zinc coated) object in place of the zinc pellet. Grow a Tin Hedgehog Pour tin chloride solution into a vial. Dont fill it up all the way because you need room for the zinc.Add the zinc pellet. Set the vial somewhere stable, so it wont get bumped or jarred.Watch the delicate tin crystals grow! Youll see the beginning of a spiky hedgehog shape in the first 15 minutes, with good crystal formation within an hour. Be sure to take pictures or video of the crystals for later, since the tin hedgehog wont last. Eventually, the weight of the fragile crystals or movement of the container will collapse the structure. The bright metallic shine of the crystals will dull over time, plus the solution will turn cloudy. Chemistry of the Reaction In this experiment, tin(II) chloride (SnCl2) reacts with zinc metal (Zn) to form tin metal (Sn) and zinc chloride (ZnCl2) via a substitution or single displacement  reaction: SnCl2   Zn → Sn ZnCl2 Zinc acts as a reducing agent, giving electrons to the tin chloride so that the tin is free to precipitate.  The reaction begins at the surface of the zinc metal. As the tin metal is produced, atoms stack on top of each other in a characteristic form or allotrope of the element. The fern-like shape of the zinc crystals is a characteristic of that metal, so while other types of metal crystals may be grown using this technique, they wont display the same appearance. Grow a Tin Hedgehog Using an Iron Nail Another way to grow tin crystals is using zinc chloride solution and iron. Unless you use a round chunk of iron, you wont get a hedgehog, but you can get the crystal growth, just the same. Materials iron wire or nail0.1 M tin chloridetest tube Note: You dont need to make up a new tin chloride solution. If you have solution from the reaction with zinc, you can use that. The concentration mainly affects how quickly the crystals grow. Procedure Suspend the iron wire or nail in a test tube containing tin chloride.After about an hour, crystals will start to form. You can examine these with a magnifying glass or by removing the wire and looking at the crystals under a microscope.Allow the iron to remain in the solution overnight for more/larger crystals. Chemical Reaction Once again, this is a  simple displacement chemical reaction: Sn2   Fe → Sn Fe2 Safety and Disposal As always, its good practice to wear safety goggles and gloves when performing chemistry experiments.When you have finished the experiment, you can rinse the chemicals down the drain with water. Learn More Use a magnifying lens to compare tin crystals grown on the zinc and iron surfaces.You may wish to experiment with how changing the concentration of the zinc chloride solution or temperature of the solution affects the crystal growth rate and appearance.Try to grow other metal crystals using this technique. Keep in mind the resulting crystals might not resemble a hedgehog. To choose a subject, find a metal salt that is soluble in water, does not oxidize too quickly in air, yet can react with zinc or iron (or other metal) to form crystals. The metal needs to be more reactive than tin or the substitution wont proceed.  Its also a good idea to consider the toxicity of the metal, for personal safety and chemical disposal. You can consult the solubility rules to select good candidates for further experimentation. Sources Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils (1985). Tin. Lehrbuch der Anorganischen Chemie (in German) (91–100 ed.). Walter de Gruyter. pp. 793–800. ISBN 3-11-007511-3.Schwartz, Mel (2002). Tin and Alloys, Properties. Encyclopedia of Materials, Parts and Finishes (2nd ed.). CRC Press. ISBN 1-56676-661-3.

Learning traditional Chinese with the MoE dictionary

Learning traditional Chinese with the MoE dictionary With access to the internet, students of Chinese have no lack of resources and tools to use, but sometimes it can be hard to find good resources for specifically for traditional characters. (Not sure about the difference between simplified and traditional Chinese? Read this!) While most resources provide both character sets, its obvious that many offer traditional characters as an after-thought or at least at lower priority than simplified characters. This means that the information about traditional characters less reliable and harder to access. Taiwans Ministry of Education Dictionaries to the rescue Fortunately, help is now available. Taiwans Ministry of Education has long provided various online dictionaries, but until recently, they were very hard to access and not well-adapted for the internet, making them less useful for foreign students. The current interface, however, is well-designed and easy to use. In this article, Im going to introduce some of all the available feature that are truly essential for students learning traditional characters. First though, heres a link to the main website: https://www.moedict.tw/ Note that theres also an app for Windows, Mac OSX, Linux, Android and iOS, which is very impressive. Its free, too, just, click the download links in the top-right corner! The main dictionary Searches on the front page will give you: Other search terms containing the query (left sidebar)Character with animated stroke order (click the character)Historical variants with animated stroke order (click æ ­ ·Ã¤ » £Ã¦â€º ¸Ã© «â€)Mark as favourite (click the star)Pronunciation (both Pinyin, Zhuyin and audio)Radical information (top right)Main reading with definitions sorted by word class (noun, verb, etc.)Additional readings with definitionsOther languages (usually Taiwanese, English, French and German) This is already very good for any dictionary, some functions are unique as far as I know (such as the historical animated stroke order). The only two problems for learners are that you need to have already reached a decent level to benefit from the Chinese-Chinese definitions and that the example sentences sometimes are historical and thus dont reflect modern usage. You dont want to uncritically add these to your spaced repetition program. Additional features The additional features are located in the navigation bar at the top of the page where it says Ã¥Å"‹è ªÅ¾Ã¨ ¾ ­Ã¥â€¦ ¸. For starters, you can access various kinds of idioms: æˆ Ã¨ ªÅ¾ (chà ©ngyÇ”), è « ºÃ¨ ªÅ¾ (ynyÇ”) and æ ­â€¡Ã¥ ¾Å'è ªÅ¾ (xiÄ“hà ²uyÇ”) by clicking 分é ¡Å¾Ã§ ´ ¢Ã¥ ¼â€¢ (fÄ“nlà ¨i suÇ’yÇ n) category index. The definitons are in Chinese, so this is again not suitable for beginners. There are also categories for loan-words (further divided into which kind of loanwords, which is hard to find elsewhere online). Further down, there are similar resources for Taiwanese and Hakka, but since this site is about learning Mandarin, they arent relevant right now. The last few menu entries are important, though, because they are some of the best resources available for Mainland and Taiwan differences in pronunciation, meaning and so on. Go down to å… ©Ã¥ ² ¸Ã¨ ©Å¾Ã¥â€¦ ¸ (liÇŽngn cà ­diÇŽn) two/both coasts (referring to Taiwan and Mainland China) dictionary and again use the category index. You now have: Ã¥ Å'Ã¥ ¯ ¦Ã§â€¢ °Ã¥   (tà ³ngshà ­ yà ¬mà ­ng) same thing, different names, listing words or phrases that mean the same thing, but are called different things on both sides of the Strait.   For example, internet (or network) is ç ¶ ²Ã¨ · ¯ (wÇŽnglà ¹) in Taiwan, but   ç ¶ ²Ã§ µ ¡ (wÇŽngluà ²) on the Mainland. Ã¥ Å'Ã¥  Ã§â€¢ °Ã¥ ¯ ¦ (tà ³ngmà ­ng yà ¬shà ­) same name, different things, listing words or phrases that look the same, but actually mean different things. For   instance, Ã¥Å"Ÿè ±â€  (tÇ”dà ²u) means potato on the Mainland, but peanut in Taiwan. è‡ ºÃ§  £Ã§â€ ¨Ã¨ ªÅ¾ (tiwÄ n yà ²ngyÇ”) Taiwanese usage lists words and phrases that are typically used in Taiwan, but not on the Mainland. Ã¥ ¤ §Ã©â„¢ ¸Ã§â€ ¨Ã¨ ªÅ¾ (dlà ¹ yà ²ngyÇ”) Mainland usage lists the opposite, i.e. language that is common on the Mainland but not in Taiwan. If you want to go back to check what you have looked-up before, just click the icon between Ã¥Å"‹è ªÅ¾Ã¨ ¾ ­Ã¥â€¦ ¸ and the cogwheels. Conclusion Overall, this dictionary easily beats any alternative when it comes to online information about traditional characters. The only drawback is that it isnt beginner friendly, but as a beginner, you can still find pronunciation and stroke order here. These are manually recorded, which means they are more reliable than any other online source. The example sentences arent perfect, but then again, there are no perfect dictionaries!