Global Warming Challenge Essay Example for Free

Global Warming Challenge Essay One of the greatest challenges earth is facing is Global Warming. The global warming hypothesis orginated in 1896 when Svante Arrhenius, a Swedish chemist, developed the theory that carbon dioxide emissions from the burning of fossil fuels would cause global temperatures to rise by trapping excess heat in the earth’s atmosphere. The term â€Å"Global Warming† signifies the temperature of the earth’s neon- surface air. The change in climatic conditions is one of the impacts of global warming. It is directly impacting on rising sea levels and the melting of ice. It is a threat to life on earth. The effects of global warming have been increasing significantly for the past decades. Climate change, devastation of the ecosystem, water contamination, melting ice over Arctic and Antarctic regions, negative impacts in the agricultural sector are just the problems caused by global warming. The reason behind this is human activities that lead to release of greenhouse gases. The concentration of greenhouse gases has significantly increased since 20th century. Some Scientists believe that there is an increase of 0.5 Celsius in earth’s temperature since 1900 and will continue to increase. The year 1990 was said to be the hottest year in the last century. We Human Beings have created an imbalance between life and nature that has led to flood, cyclones, landslides, tsunami, drought, etc. If this imbalance continues, soon our life on earth would be difficult. The increase of Carbon-dioxide in air is one of the reasons for warming the earth’s surface. The most significant greenhouse gas is actually water vapor, not something produced directly by humankind in significant amounts. However, even slight increases in atmospheric levels of carbon dioxide (CO2) can cause a substantial increase in temperature. When the earth’s surface warms up it will eventually lead to evaporation of water. Water vapor, itself is a greenhouse gas. It is believed that the increase in CO2 in the atmosphere will continue due to ongoing burning of fossil fuels and deforestation. Not only CO2 but other gases such as methane, CFCs, nitrous oxide, tropospheric ozone are also responsible for global warming. The increase in these gases is due to industrialization, deforestation, urbanization and increasing population. Nature has given us a mechanism to decrease the content of CO2 in atmosphere but we are exploiting it. Trees are the mechanism given to mankind as a gift from nature. Trees convert CO2 gas into Oxygen. This helps to decrease the CO2 content in atmosphere which eventually helps us prevent  global warming. The question that should be put forward now is that if this mechanism only won’t exist then how will we prevent global warming? Human beings have always been exploiting nature. Trees have been cut down for the benefits of humans without realizing that it is going to affect us eventually. Deforestation is responsible for 25 per cent of all carbon emissions entering the atmosphere, by the burning and cutting of 34 million acres of trees each year. Everyday over 5500 acres of rainforest are destroyed. Increasing population is also one of the reasons for global warming. Approximately, 80 per cent of atmospheric C02 increases are due to man’s use of fossil fuels either in the form of coal, gas or oil. Vehicles with poor gas mileage contribute the most to global warming. Besides, the sulphur group gas is the most harmful for this. Its contribution is 30 per cent in global warming. This gas is also emitted from the burning of fossil fuels. One of the effects of global warming is rise in sea-level. It will lead to melting of glaciers and changes in rainfall patterns. The rate of melting glaciers have been increasing since the past decade. . The shrinking of glaciers is going to pose a major problem of drinking water. The sea levels as a result of melting of glaciers have risen from 0.35 mm to 0.4 mm. Scientists have warned in their reports that most of the glaciers will disappear within a period of 15 to 25 years. It will create problems of drinking water and food grains in most of the North American countries. India is not unaffected from it. The Himalayan glaciers have shrunk about 30 per cent after 1970. The rise in sea levels is a major cause of concern. A large number of cities located in coastal areas will submerge in the sea. Besides, many island countries will ultimately lose their existence and will be washed away from the surface of the earth. In India this effects may also threaten the Lakshadweep islands, Mu mbai and deltas of Ganges (West Bengal), Carvers (T.N), Godavari (AP) and Mahanadi, Orissa. India is also affected by global warming. As India is an agricultural country, it is largely dependent on rainfall but due to irregular rainfalls caused by global warming, the yield is decreasing every year. The rise in atmospheric temperature and fall in rain would naturally result in decline in crop production. Moreover, it would have great effect on biodiversity as well. Forestation can be of great help in this regard. Planting more trees worldwide will help restore the imbalance. Secondly, we must follow on environmental policy of ‘reduce,  reuse, recycle’, i.e. promoting the reuse of anything. Thirdly, the use of fuel-efficient vehicles should be promoted as these vehicles have lower emissions of harmful gases. Fourthly, every individual should be aware of the importance of the protecting environment. Besides, eco- friendly technologies must be promoted, and must be substituted with the technologies which cause great emission of global warming gases. Many government agencies around the world are very interested in maintaining fossil fuel use, especially coal. Furthermore, we are not going to run out of coal in the near term (oil may begin to run low sometime after 2010). Methods for reducing carbon emission levels while still burning coal are now investigation by government and industry, as we now discuss. It is too late to debate on global warming. We need to take some measures to decrease global warming. Forestation can be of great help in this regard. Planting more trees worldwide will help restore the imbalance. Secondly, we must follow on environmental policy of ‘reduce, reuse, recycle’, i.e. promoting the reuse of anything. Thirdly, the use of fuel-efficient vehicles should be promoted as these vehicles have lower emissions of harmful gases. Fourthly, every individual should be aware of the importance of the protecting environment. Besides, eco- friendly technologies must be promoted, and must be substituted with the technologies which cause great emission of global warming gases. We should control the growth of population by decreasing birth rate. This can be done by proper family planning. We should reduce the use of chlorofloro carbons. More use of non-conventional source of energy like wind power and solar energy. It is said that â€Å"There is no place like home† and earth is our home so we need to protect it. Policies are made every day but do we follow it? The answer is â€Å"No†. We all are aware of global warming so we need to change the way we think that we can’t do anything and only the rich who are seated in the seats of government can save us. Who you are, whatever you are you can do something for your planet when you think global warming is a problem.

Decriminalization Of Marijuana :: legalization of hash

This nation's so-called war on drugs has been a miserable failure. It hasn't' worked. The drug problem is getting worse. I think it is the number one problem facing this country today. I think that we as people and our politicians really need to put all of our options into perspective, and one of the things we need to talk about is decriminilization.   Ã‚  Ã‚  Ã‚  Ã‚  Common sense or logic would dictate that when you take this issue on, when you talk about legalization or decriminalization, if you are going to talk about that, you are going to have to talk about taking it in steps, and certainly the first step would be marijuana. All of us can make a list out of friends that have used drugs. Are our friends criminals for using drugs? Yes, they are today given the laws that we have. Should they be criminals? Are they criminals? For the most part, no they are not. We are talking about federal law, and I see this as a national issue which is an extremely tough issue with politicians. There isn't a bigger taboo topic because if you're going to talk about legalization, you're talking about making it readily available for kids, but I read in a poll that 95 percent of kids in high school say illegal drugs are readily available. I know this is a fact because I once was a high school student and had the unfortunate experience to see this all around me. I don't know how it gets more readily available than that. I'm not advocating breaking the law, but personally, I don't think you should go to jail for smoking marijuana. I think 75 percent of the people in this country would say, no, you shouldn't go to jail for smoking marijuana.   Ã‚  Ã‚  Ã‚  Ã‚  700,000 Americans are in jail or prison on drug related charges. That is something I have a problem with and think we as people and a democratic country is something we need to deal with. I am very confused about this issue and I am deeply concerned and feel this is something that needs to be dealt with and handled properly according to the facts. I am talking about legalization and decriminalization, but I'm definitely not condoning drug use. From what I know and what I see as an American citizen on a day to day basis it seems like there is no political support and no one is trying to do anything about it. We're spending more and we're locking more people up for drug use in today's society which is a definite cause of the overcrowded prisons in our country.

Jean-Baptiste Carpeaux Essay -- essays research papers

Jean-Baptiste Carpeaux 1827 - 1875 The son and grandson of stonemasons, Jean-Baptiste Carpeaux was born in 1827 in Valenciennes and moved to Paris at the age of eleven. Beginning in the early 1840s he studied at the Petite Ecole, the state school for training in the applied arts, formally called the Ecole Gratuite de Dessin, before entering the Ecole des Beaux-Arts in 1844, where he changed masters repeatedly, oscillating between typical student ambition (optimal credentials for the Prix de Rome) and his interest in more liberal approaches. Carpeaux moved from Ecole painter Abel de Pujol (1785-1861), to the independent sculptor Franà §ois Rude, and finally to the prestigious Ecole sculptor Francisque-Joseph Duret (1804-1865). After winning lesser competitions--despite being caught cheating--Carpeaux was awarded the Prix de Rome in 1854, but outstanding imperial commissions and illness delayed his departure until 1856. Once in Rome Carpeaux intensified his reputation as institutional bad boy, canny professional maneuverer, and provocative artist. As a pensionnaire he battled repeatedly with the Villa Medici authorities and flouted Ecole policy. Yet his major envois--the Neapolitan Fisherboy and multi-figural Ugolino (both begun 1857)--introduced his name in Paris and provided the artistic and commercial germs for his entire life. His pre-eminence, as the star among emerging sculptors, was established at the Salon of 1863, where he exhibited finished versions of those two works...

Euglena Research Paper

The effect of fertilized water on growth of Euglena Water is a good habitat for many organisms. The pureness of water has strong effect on aquatic organism (Walter, 2008). The altering of water condition could favor for the growth of one certain organism, but less favor for other organisms that leads to the competing out other organism by abundance of favor one . So, the result goes to decreasing of water biodiversity. Water ecology, which studies on the interaction between of biotic and abiotic factors to the growth of organism in water, is too important in order to keep the ecosystem balance.In our study, we focused on how the fertilize (nitro, phosphorus) effects on the populations of water organisms. Euglena is the mixotrophic which could synthesis energy from photosynthesis, but also could consume the food to make energy (Robert. et al, 2012). From the trophic characteristic of Euglena, my hypothesis for this study was the population of Euglena would increase in the rich fertili ze environment. The rationale for my hypothesis was Euglena could consume the food to have energy, so the rich fertilize environment was a good source for growth and reproduction of Euglena, that’s why their population would increase by time.The water from American river was collected for our sample. We set up three different ecosystems for organisms in three different jars: control, low fertilize and high fertilize environment. First river water was added to the jar, then organisms was added and the different amount of fertilize was put last to appropriate jar. We were helped to identify each organism under microscope. Before adding organism to ecosystems, counting sample had been done. The sampling was done every week through 3 weeks.After 3 weeks, the number of organisms of Euglena and other heterotrophic in each ecosystem was used to plot graphs and analysis. The population of Euglena in control condition increased in first two weeks, and then it decreased. In the low and high fertilize condition; the population of Euglena was very low and at the constant after 3 weeks. (Figure 1) My hypothesis was not supported from result. Euglena population in the high fertilize jar didn’t increase as we predicted. In contrast, the population of Euglena in the control jar increased. From our observed, there were abundant of green algae in the fertilized jar.This observing was matched with the statement that the high amount of nitro and phosphor could lead to the boom of green alga, and the high production of green algae could compete out other organism in the water (N, 1999). Green alga covered on the surface of the jar that inhibited the photosynthesis of Euglena. Then other question was asked, Euglena could consume the food to make energy, but why their population didn’t increase in the rich nutrient environment. Other hypothesis was stated by us: in the higher fertilize condition; the population of other heterotrophic would increase.The rationale was other heterotrophic could use the food source more effective than Euglena. Euglena didn’t have enough time to convert from photoautotroph to heterotrophic mode, so they could not use the food source to growth (Hall, 1939). The second hypothesis was supported when the population of other heterotrophic first increased in fertilized water, and then by time, after food was used up, the population started to decrease (figure 2). From our results, we could conclude that fertilize which is defined as a good source for plant but could polluted the water (2008) effects on the growth of other organism.It could make the imbalance ecosystem because of the abundance of one specie and extinct of other species. So, keeping water clean is very important task to be concerned. Figure 1: The populations of Euglena in control, low fertilize and high fertilize environment through 3 weeks. Figure 1: The populations of Euglena in control, low fertilize and high fertilize environment through 3 weeks. Figure 2: The populations of other heterotroph in control, low fertilize and high fertilize environment through 3 weeks Figure 2: The populations of other heterotroph in control, low fertilize and high fertilize environment through 3 weeksLiterature Cited: Dodds. K. W (2008). Fresh water ecology: concept and environmental application of limnology (2nd ed. ) San Francisco: Elsevier. Hall, R. P. , & Schoenborn, H. W. (1939). The question of autotrophic nutrition in Euglena gracilis. Physiol Zool, 12(1), 76-84. Sanders, R. , & Gast, R. (2012). Bacterivory by phototrophic picoplankton and nanoplankton in arctic waters. FEMS Microbiology Ecology, 82(2), 242-253. Sharply. A. N,Daniel. T &Sim. T (1999). Agriculture phosphorus and eutrophication. Washington: United Department of Agricultural.

Essay on American Government and Politics Part 3

Essay on American Government and Politics Part 3 Essay on American Government and Politics Part 3 Essay on American Government and Politics Part 3Continue Part 2Needles is the first chapter of the book that gives insight into the early life of Sonia Sotomayor. The author describes her early life and her environment.At home is the second chapter, where the author describes her home and her family members in details.Abuelita is the third chapter, where the author describes her childhood and her friends and uncovers her reliance on her friends and importance of friendly relations for her.Gilmars goodbyes is the fourth chapter that gives insight into interpersonal relations of the author with her friends and uncovers her background.Trips to Puerto Rico is the fifth chapter, where the author continues to uncover her background and emphasizes her Hispanic origin. In this chapter, the author uncovers the brief history of her family and its strong links to Puerto Rico.Papis death is the sixth chapter that reveals a tragic moment in the life of the child, the death of her father. However, Sonia is not really disappointed by this death because her father was alcoholic and died, when she was just nine.El luto is the seventh chapter, where the author depicts her struggle with her first problems and recovery after the death of her father.Celinas story is the eighth chapter, where the author reveals the growing role of her grandmother, who became the main care giver for her.Transformation is the ninth chapter, which conveys the profound change that occurred to the narrator and shows how a girl has started to change under the impact of hardships that occurred to her life.Diabetes, Nancy Drew, Perry Mason is the tenth chapter revealing the main health issue that Sonia confronted at the early age. She was diagnosed with diabetes and had to learn how to live with a new health problem.Middle school is the eleventh chapter, where the author describes her middle school experience and her success in the academic development. She describes her early interest to law that determine d the choice of her future career.Transition to CSHS, first job is the twelfth chapter that shows her early professional experience and her first job, which became a considerable contribution to her further professional development.Quotesâ€Å"One thing has not changed: to doubt the worth of minority students achievement when they succeed is really only to present another face of the prejudice that would deny them a chance to even try. It is the same prejudice that insists all those destined for success must be cast from the same mold as those who have succeeded before them, a view that experience has already proven a fallacy.† (Sotomayor,   2014, 121)This quote reveals the experience of the author as a minority student. At the same time, this quote may be viewed in the broader sense since the quote uncovers the minority-majority relationship. The author stands on the ground that the majority always underestimates the potential and achievement of representatives of minority groups. The relationship between the minority and majority is always very complicated , while the author develops the idea of the determinant role of prejudices and stereotypes which affect their relationship. According to the author, the impact of prejudices and stereotypes on the perception of the minority by the majority is overwhelming. Therefore, prejudices and stereotypes influence policies conducted by the policy makers, who represent the majority mainly. In such a situation, representatives of the minority need the adequate representation as well as they need to change the existing biases and stereotypes to prove that they are equal to representatives of the majority. In this regard, the education and professional development of Sotomayor have revealed how difficult it was for her to overcome prejudices and biases in relation of other people to her because of her Hispanic background.  Ã¢â‚¬Å"Quiet pragmatism, of course, lacks the romance of vocal militancy. But I felt mys elf more a mediator than a crusader. My strengths were reasoning, crafting compromises, finding the good and the good faith on both sides of an argument, and using that to build a bridge.† (Sotomayor,   2014, 154).This quote reveals the pragmatism and flexibility of the narrator of the book. At the same time, this quote shows how important are pragmatism and diplomacy in politics and relations between people. The ability to negotiate, to compromise and to build a bridge is very important for the development of effective policies or international relations. In fact, this quote reveals the effective way to building bridges between the minority and majority as well as between different social groups. Negotiations, arguments, understanding of both sides are crucial for the development of effective relations and policies that can respect and match interests of all stakeholders. This model can be applied at the local, national or international level with equal success. The author refers to her personal experience in developing positive and successful relations with other people but this model is broader and may be applied to different fields.

What Does it Mean to be a Capitalist Economy †Political Science Essay

What Does it Mean to be a Capitalist Economy – Political Science Essay Free Online Research Papers What Does it Mean to be a Capitalist Economy Political Science Essay Capitalism is defined as an economic system in which the means of production are mostly privately owned, and capital is invested in the production, distribution, and other trade of goods and services, for profit in a competitive free market. The concept of â€Å"classical† capitalism is said to have emerged in the late 18th century. â€Å"The classical, political economists: Adam Smith, Jean-Baptiste Say, John Stuart Mill, and David Ricardo published analyses of the production, distribution, and exchange of goods in a capitalist economy that have since formed the basis of study for most contemporary economists.† from J. K. Galbraith’s American Capitalism In a capitalist economy, privately owned corporations and businesses control the entire economy. This is probably this most popular economic view, a small farmer can buy his neighbor’s small farm for a set amount of money, and buy his neighbor’s neighbor’s small farm, and so on. Eventually the farmer can buy out all of his surrounding farms and create a monopoly. A monopoly is defined as a persistent market situation where there is only one provider of a product or service. Monopolies are normally characterized by a lack of economic competition for the good or service that they provide and a lack of viable substitutable goods. There are laws in the United States regulating the creation of monopolies in an attempt to keep the free market fair. The barriers for business or organizations to become a monopoly are great. There are two acts in the United States that have attempted to prevent, or slow down potential monopolies: The Sherman Anti-Trust Act and the Clayto n Act. The Sherman Anti-Trust Act was the first U.S. federal government action to limit monopolies. It was enacted on July 2, 1890. The Clayton Anti-Trust Act was enacted in 1914 to remedy deficiencies in antitrust law created under the Sherman Anti-Trust Act that allowed corporations to dissolve labor unions. The Clayton Act filled in the gaps of the Sherman Anti-Trust Act by preventing price discriminations, and from people being involved in two competing organizations. With these laws in place in the American law system it is unlawful for any one company to gain control of all its competitors and become one corporate â€Å"giant†. The nons of this would be cable television, phone, and electricity. These examples are sometimes able to charge higher fees because they are the only company in that field available to you, but because they are considered a utility, they are not a monopoly. The price of gas is another example. When there is a situation in the Middle East, the price of gas seems to go up. The reason we are given is, because it is costing us more to get the product out of the Middle East. The problem with that explanation is that only about 15% of the nations gas consumption is from foreign sources, majority of our resource is domestic. The reason gas prices go up is because we no longer have the option of the getting the cheaper Middle Eastern gas, and can now be gorged by our domestic companies. Capitalism, inevitably, results in unequal wealth distribution. In actual practice it appears that as the ranks of the wealthy grow the ranks of the poor also increase. At least that seems to be what is happening in the United States. It also appears that wherever there are great disparities of wealth in an area crime increases dramatically. Another negative result of unrestrained capitalism is that the wealthy have little need to spend all of their wealth, so that they keep a great deal of the total wealth of the country invested and growing more family fortunes. As a result they can send their children to better schools getting better educations, and creating an ever-increasing gap between classes. The poor have more need to spend all of their income on the necessities, therefore can save little and accumulate little or no capital growth. In a capitalist society the wealthy have disproportionate power to influence legislation which inevitably favors themselves, often at the expens e of the less affluent. This also, all too often, results in the corruption of government officials, and increase of white-collar crime. Although the wealthy provide the means of developing the natural resources of a nation, they often contribute mightily to its pollution and degradation. I think it could be argued that the streams and forests and minerals of the country ought to belong to all of its citizens, not the wealthy who gain access to strip mine and deforest or drill at the expense of an environment that we all share. Even though we may concede that capitalism is the most successful among the economic systems, we must recognize that it is not without negative aspects or that there is no room for improvements. The smug American attitude which assumes that we excel at everything overlooks areas in which we might benefit by studying how someone else does things. The complexity and chaos of a health care system which leaves 45 million citizens to the mercy of emergency room treatment for minor ailments, which costs the taxpayers a higher percentage of gross national income than any other nation, might well benefit by adapting some of the methods of those countries which cover all of their citizens with lower costs and better results. Socialist and communist countries have often outstripped us in such areas as education and health care, and it makes sense that we ought to imitate whatever aspect of their successes would prove advantageous to ourselves. We first need to acknowledge that there is room f or improvement in our still imperfect society. The nons of this would be cable television, phone, and electricity. These examples are sometimes able to charge higher fees because they are the only company in that field available to you, but because they are considered a utility, they are not a monopoly. The price of gas is another example. When there is a situation in the Middle East, the price of gas seems to go up. The reason we are given is because it is costing us more to get the product out of the Middle East. The problem I have with that explanation is that only about 15% of the nations gas consumption is from foreign sources, majority of our resource is domestic. The reason gas prices go up is because we no longer have the option of the getting the cheaper Middle East gas, and can now be gorged by our domestic companies. Capitalism inevitably results in unequal wealth distribution. In actual practice it appears that as the ranks of the wealthy grow the ranks of the poor also increase. At least that seems to be what is happening in the United States. It also appears that wherever there are great disparities of wealth in an area crime increases dramatically. Another negative result of unrestrained capitalism is that the wealthy have little need to spend all of their wealth, so that they keep a great deal of the total wealth of the country invested and growing more family fortunes. As a result they can send their children to better schools getting better educations, and creating an ever-increasing gap between classes. The poor have more need to spend all of their income on the necessities, therefore can save little and accumulate little or no capital growth. In a capitalist society the wealthy have disproportionate power to influence legislation which inevitably favors themselves, often at the expense of the less affluent. This also, all too often, results in the corruption of government officials, and increase of white-collar crime. Although the wealthy provide the means of developing the natural resources of a nation, they often contribute mightily to its pollution and degradation. I think it could be argued that the streams and forests and minerals of the country ought to belong to all of its citizens, not the wealthy who gain access to strip mine and deforest or drill at the expense of an environment that we all share. Even though we may concede that capitalism is the most successful among the economic systems, we must recognize that it is not without negative aspects or that there is no room for improvements. The smug American attitude which assumes that we excel at everything overlooks areas in which we might benefit by studying how someone else does things. The complexity and chaos of a health care system which leaves 45 million citizens to the mercy of emergency room treatment for minor ailments, which costs the taxpayers a higher percentage of gross national income than any other nation, might well benefit by adapting some of the methods of those countries which cover all of their citizens with lower costs and better results. Socialist and communist countries have often outstripped us in such areas as education and health care, and it makes sense that we ought to imitate whatever aspect of their successes would prove advantageous to ourselves. We first need to acknowledge that there is room f or improvement in our still imperfect society. My final view on capitalism is that in a country, the United States, which promotes all types of equality, uses an economic system that promotes economic inequality. I say that because within modern market economies is because wages are determined by a market, and are hence influenced by supply and demand. In this view, inequality is caused by the differences in the supply and demand for different types of work. Also capitalism can lead to a type of government known as Imperialism. â€Å"Imperialism is a policy of extending control or authority over foreign entities as a means of acquisition and/or maintenance of empires. This is either through direct territorial conquest or settlement, or through indirect methods of exerting control on the politics and/or economy of these other entities. The term is often used to describe the policy of a nations dominance over distant lands, regardless of whether the nation considers itself part of the empire.† –Wikipedia’s definition of Imperialism. . Research Papers on What Does it Mean to be a Capitalist Economy - Political Science EssayAssess the importance of Nationalism 1815-1850 EuropeTwilight of the UAWThe Effects of Illegal ImmigrationPETSTEL analysis of IndiaDefinition of Export QuotasNever Been Kicked Out of a Place This NiceAnalysis of Ebay Expanding into AsiaQuebec and CanadaMarketing of Lifeboy Soap A Unilever Product19 Century Society: A Deeply Divided Era

Atomic Mass Unit Definition (AMU)

Atomic Mass Unit Definition (AMU) In chemistry, an atomic mass unit or AMUÂ  is a physical constant equal to one-twelfth of the mass of an unbound atom of carbon-12. It is a unit of mass used to express atomic masses and molecular masses. When the mass is expressed in AMU, it roughly reflects the sum of the number of protons and neutrons in the atomic nucleus (electrons have so much less mass that they are assumed to have a negligible effect). The symbol for the unit is u (unified atomic mass unit) or Da (Dalton), although AMUÂ  may still be used. 1 u 1 Da 1 amu (in modern usage) 1 g/mol Also Known As:Â  unified atomic mass unit (u), Dalton (Da), universal mass unit, either amu or AMU is an acceptable acronym for atomic mass unit The unified atomic mass unit is a physical constant that is accepted for use in the SI measurement system. It replaces the atomic mass unit (without the unified part) and is the mass of one nucleon (either a proton or a neutron) of a neutral carbon-12 atom in its ground state. Technically, the amu is the unit that was based on oxygen-16 until 1961, when it was redefined based on carbon-12. Today, people use the phrase atomic mass unit, but what they mean is unified atomic mass unit. One unified atomic mass unit is equal to: 1.66 yoctograms1.66053904020 x 10-27 kg1.66053904020 x 10-24 g931.49409511 MeV/c21822.8839 me History of the Atomic Mass Unit John Dalton first suggested a means of expressing relative atomic mass in 1803. He proposed the use of hydrogen-1 (protium). Wilhelm Ostwald suggested that relative atomic mass would be better if expressed in terms of 1/16th the mass of oxygen. When the existence of isotopes was discovered in 1912 and isotopic oxygen in 1929, the definition based on oxygen became confusing. Some scientists used an AMU based on the natural abundance of oxygen, while others used an AMU based on the oxygen-16 isotope. So, in 1961 the decision was made to use carbon-12 as the basis for the unit (to avoid any confusion with an oxygen-defined unit). The new unit was given the symbol u to replace amu, plus some scientists called the new unit a Dalton. However, u and Da were not universally adopted. Many scientists kept using the amu, just recognizing it was now based on carbon rather than oxygen. At present, values expressed in u, AMU, amu, and Da all describe the exact same measure. Examples of Values Expressed in Atomic Mass Units A hydrogen-1 atom has a mass of 1.007 u (or Da or amu).A carbon-12 atom is defined as having a mass of 12 u.The largest known protein, titin, has a mass of 3 x 106 Da.AMU is used to differentiate between isotopes. An atom of U-235, for example, has a lower AMU than one of U-238, since they differ by the number of neutrons in the atom.