How Chemical Hand Warmers Work

If your fingers are cold or your muscles ache, you can use chemical hand warmers to heat them up. There are two types of chemical hand warmer  products, both using exothermic (heat-producing) chemical reactions. Here is how they work. Key Takeaways: Chemical Hand Warmers Chemical hand warmers rely on exothermic chemical reactions to release heat.There are two main types of chemical hand warmers. One type releases heat by air activation. The other type releases heat when a supersaturated solution crystallizes.Air-activated hand warmers are single use products. Chemical solution hand warmers are re-usable. How Air Activated Hand Warmers Work Air-activated hand warmers are long-lasting chemical hand warmers that start working as soon as you unseal the packaging, exposing it to oxygen in​ the  air. The packets of chemicals produce heat from oxidizing iron into iron oxide (Fe2O3) or rust. Each packet contains iron,  cellulose (or sawdust -- to bulk up the product), water, vermiculite (serves as a water reservoir), activated carbon (distributes heat uniformly),  and salt (acts as a catalyst). This type of hand warmer produces heat anywhere from 1 to 10 hours. Its common to shake the packets to improve circulation, which speeds the reaction and increases the heat. Its possible to get a burn from direct contact between the hand warmer and skin, so the packaging warns users to put the product on the  outside a sock or glove and to keep the packets away from children, who could get burned more easily. Air-activated hand warmers cannot be re-used once they have stopped heating. How Chemical Solution Hand Warmers Work The other type of chemical hand warmer relies on crystallization of a supersaturated solution. The crystallization process releases heat. These hand warmers dont last as long (usually 20 minutes to 2 hours), but they are re-usable. The most common chemical inside this product  is a supersaturated solution of sodium acetate in water. The product is activated by flexing a small metal disk or strip, which acts as a nucleation surface for crystal growth. Usually, the metal is stainless steel.  As the sodium acetate crystallizes, heat is released (up to 130 degrees Fahrenheit). The product can be recharged by heating the pad in boiling  water, which dissolves the crystals back into the small amount of water. Once the package cools, it is ready to use again. Sodium acetate is a food-grade, non-toxic chemical, but other chemicals can be used. Some chemical hand warmers use supersaturated calcium nitrate, which is also safe. Other Types of Hand Warmers In addition to chemical hand warmers, you can get battery-operated hand warmers and also products that work by burning lighter fluid or charcoal inside special cases. All of the products are effective. Which you choose depends on the temperature you want, how long you need the heat to last, and whether you need to be able to re-charge the product. How to Make a Chemical Hand Warmer Its easy to make a DIY hand warmer using iron, salt, and water in a plastic bag. Materials Iron filingsSalt (sodium chloride)Warm (not hot) waterSand, sawdust, vermiculite, or sodium polyacrylate gelZip-top plastic bags Procedure In a small zip-top bag, mix 1-1/2 tablespoons iron filings, 1-1/1 tablespoons salt, 1-1/2 tablespoons sand (or other absorbent material), and 1-1/2 tablespoons warm water.Squeeze the air out of the plastic bag and seal it.Its a good idea to place the bag of chemical inside another bag, remove the excess air, and seal it.Shake or squeeze the content of the bag for about 30 seconds to mix the contents and form a slush. The bag will get hot and will remain hot as long as the chemical reaction proceeds. If the bag gets too hot to hold, set it down. Dont get burned! Another option is to wrap the bag in a sock or towel. This is an air-activated hand warmer. Even though most of the air is squeezed out, enough remains in the bag for the oxidation reaction. If you closely examine the contents of the bag after the reaction is complete, youll see the iron has changed into iron oxide or rust. This type of reaction cannot be reversed unless energy is added, so the hand warmer cannot be re-used. If you want to prepare a homemade hand warmer for later use, keep the salt and water separate from the iron and filler until youre ready for the reaction to occur. Sources Clayden, Jonathan; Greeves, Nick; Warren, Stuart; Wothers, Peter (2001). Organic Chemistry (1st ed.). Oxford University Press. ISBN 978-0-19-850346-0.Dinà §er, Ibrahim; Rosen, Marc (2002). Thermal Energy Storage (TES) Methods. Thermal Energy Storage: Systems and Applications (1st ed.). John Wiley Sons. ISBN 0-471-49573-5.Hakkin Warmers Co. Ltd. History. www.hakukin.co.jp

David Moore s On Nature Vs. Nurture - 1230 Words

Ryan Babakhani Anthropology 423 Christina Campbell October 9, 2017 David Moore’s Take on Nature vs. Nurture Traditionally, studies of various organisms have highlighted the importance of genetics as the main determinant of the traits and behaviors that characterize them. This goes back to the Darwinian Theory, which categorized beauty and glamour as results of â€Å"good† genes and the existence of evil and depression as consequences of â€Å"bad† genes. The idea that genes are the critical determining factor of traits and behaviors, and that environmental conditions have little to no effect on the development of these traits, prevailed for several decades within the scientific community. This misconception falls under the umbrella of the nature†¦show more content†¦Moore discusses several examples that weaken genetic determinism: the number of fingers and toes an individual is born with, for example, is has always been assumed to be strictly the result of one’s genetics. However, an alternative viewpoint is that without a healthy genome, or mutation-free genetic environment, an organism’s finger and toe count may vary. Although Moore’s argument does not take away from the significance of studying genetics, it makes a strong cas e for the idea that genes and environment must be considered in conjunction during the analysis of traits and behaviors. Moore offers a great analogy for this pairing, stating that both the wheels and the chain of a bicycle are necessary in order for it to function properly. Nature and nurture are the wheels and the chain of trait-development. Furthermore, diseases that were previously categorized as genetic, and even some that were believed to be caused by a single gene, have been assessed for potential environmental causes that go beyond genetics. In fact, as Moore quoted in his book, the Centers for Disease Control’s panel stated that â€Å"As we acquire more knowledge about the molecular basis of genetic disease, it becomes increasingly clear that variable expressivity (i.e. modification of a genetic trait by other genes or the environment) is the rule rather than the exception† (pp. 23). Combinations of genetic and environmental conditions may contribute to these â€Å"genetic†Show MoreRelatedNature Vs Nurture : Nature Or Nurture874 Words   |  4 Pages Nature or Nurture. Nature may be all of the genes and hereditary factors with which influence them to become who they are such as physical appearances and personality characteristics. Nurturing impacts people’s lives as well as how they are raised and all the environmental factors. In combination, these qualities can be the true identity of oneself. Many people may argue that nurture appears to a play huge factor in the two, but others may think otherwise. Not having both as a characteristic canRead MoreThe Other Wes Moore And Its Consequences889 Words   |  4 PagesPoverty is one of the main subject matters that is present in the book of The Other Wes Moore, and its consequences are revealed through various outcomes that are being portrayed by both characters. Poverty is being characterized through the social environment that both characters live in. Both Wes Moore’s were living in an environment that had an impact not only on the way they behave, but also their psyc hological behaviour. â€Å"Living in the Bronx and Baltimore had given me the foolish impressionRead MoreHomosexuality - Nature or Nurture Essay2535 Words   |  11 PagesHomosexuality Nature or Nurture Have you ever wondered what creates a persons sexual preference? 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Christensen H A R VA R D B U S I N E S S R E V I E W P R E S S BOSTON, MASSACHUSETTS 100092 00 i-vi r1 rr.qxp 5/13/11 6:52 PM Page iv Copyright 2011 Jeff Dyer, Hal Gregersen, and Clayton M. Christensen All rights reserved Printed in the United States of America 10 9 8 7 6 5 4Read MoreOrganisational Theory230255 Words   |  922 Pagesmanaging, organizing and reflecting on both formal and informal structures, and in this respect you will find this book timely, interesting and valuable. Peter Holdt Christensen, Associate Professor, Copenhagen Business School, Denmark McAuley et al.’s book is thought-provoking, witty and highly relevant for understanding contemporary organizational dilemmas. 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Aztecs Essay Example For Students

Aztecs Essay The Aztec people ruled from the Gulf of Mexico to present day Guatemala. There capital city was Tenochititlan. The greatest controlling force was religion. It was shown in their architecture and sculpture. They also had writing, numbers and a calendar. They had recorded dates for religious holidays. The children were taught respect, courtesy, truthfulness and self control. Aztec boys learned practical tasks from their fathers at home. Then when they reached 15 they went to a youth house. There elders taught the boys religion, citizenship, history, traditions and art. They also learned war. Girls could also learn to be priestesses in temple schools. The Aztecs were divided into tribes that were dived into clans. Each clan had its own officials that represented them at tribal meetings. The land was dived up by the tribes. They controlled the land but the peasants farmed it having to give some of it to the chiefs and priests. The Aztecs worshipped a host of gods that represented nature. To win the gods aid they performed rituals and offered penance. Human sacrifice played an important role. Since life was a mans most valued possession it was the best thing to offer up to the gods. As the Aztec empire grew so did the human sacrifice. Sometimes the Aztecs performed cannibalism, believing they absorb the virtues of the slain. The sacrificed people were thought to be given a high place in heaven. The average Aztec was a farmer. He lived outside the city and grew crops for his tribe. Farming was the most important means of survival due to the warm, humid climate. They lived in small huts. The male was the head of the family. He would often arrange marriages for their children. The language they spoke was the Nahuan language that originated from the west coast of the united states. They wore elaborate colorful clothing made from animal skins that were traded from northern tribes. I personally like the cities they built. The did not have the wheel yet they built some of the most beautiful cities in the world. They were at their prime when the Spanish arrived. They saw their practices and considered them barbaric. They destroyed all but a few records of them and tried to convert them. even though they were almost destroyed the Aztec people live on in present day Mexicans today.Category: History

The Island By Gary Paulsen Essays - WIL, , Term Papers

The Island by Gary Paulsen The book I read was The Island by Gary Paulsen. It is about a 15 year old boy named Wil Neuton who moves with his family to northern Wisconsin. There he finds an island on Sucker Lake where he stays to learn about himself. Wil likes riding his bike early in the morning. He also likes watching nature. He is very tall for his age-6 feet 2-but well-built and strong. He is honest,cares about others and prefers to talk things through than resort to violence. The title is good because the book is very much about the island and about Wil finding himself on this island. The island also becomes a very prominent point in Wil's life. By comparison and observation, he learns that all things are connected. An interesting minor character is Emil Aucht. On the morning of his first day in Pinewood Wil wakes up to find Emil staring at him through the window. Emil is an old man with one tooth, no hair and ears that stick out. He chews tobacco and spits brown gunk all over the place. He first appears in the story to request that Wil help him get his car out of the mud. Then Emil reappears to fix the plumbing,wrecking Wil's parents' nerves in the process. The atmosphere in the story is that of a small hick town in northern Wisconsin:open,friendly,relaxed and very laid-back. It strikes me as being very much like "cottage country" in northern Ontario:lakes,forest,fishing,small town life. The time is the late 1980's. The novel ends with Wil seeing that his father is watching him from shore. Wil rows over and finds that his father is tired and sad,his eyes rimmed with red from crying. Wil invites his father over to the island and realizes that this saga will only end when Wil finds an island big enough for his whole family so they can learn what he has learned. I feel that the most interesting part of the book is the beginning of each chapter where there is a paragraph by Wil himself about life and other important pieces of trivia. It offers insight into Wil's personality and gives his views on many subjects. In conclusion,I think this is a good book for people my age. It stresses the importance of knowing who you are and of saving the environment. I enjoyed it and it really made me think.