Many advanced high school and college chemistry students perform an experiment known as the "iodine-clock" reaction‚ in which hydrogen peroxide reacts with iodide to form iodine‚ and the iodine subsequently reacts with thiosulfate ion until the thiosulfate has been consumed. At that point‚ the reaction solutions turn blue in the presence of starch. The experiment helps students understand the fundamentals of chemical kinetics --- the speeds at which reactions take place. 1. Activation Energy
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approached the end of his presidency in 1816‚ a fellow Virginian and Republican—James Monroe—was elected as his successor. Monroe’s presidency was a continuation of the so-called “Virginia Dynasty‚” since all of the presidents between 1801 and 1825 were from Virginia. The fading Federalist Party ran a candidate in the 1816 election for the last time‚ securing only 34 electoral votes compared to Monroe’s 183 votes. Monroe came to the presidency with a solid political background; he had served as a U.S
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Analysis The 13 Clocks is a fairy tale told by a twentieth century author. Its themes are clearly statements about the moral concerns of the time and perhaps are intended more for adults than for children‚ even though James Thurber used the form of a child’s story. One of the story’s meanings is that a true life is in a way being like a child. Adults responded to Thurber’s message: The book sold well‚ going into nine printings. Thurber had earlier written fairy tales for children as well as
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Marilyn Monroe and her many affairs? Could the U.S. government have anything to do with her sudden and unexpected death? Whatever the answers to these questions are‚ one thing is certain; there are too many unanswered questions for Monroe’s death to be a simple answer like suicide. Although Marilyn Monroe has been one of the most prominent and influential figures in Hollywood‚ she had to endure numerous hardships before she ultimately became known as a world famous actress and model. Monroe was born
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Monroe Doctrine The Monroe Doctrine can be considered as the United States first major declaration to the world as a fairly new nation. The Monroe Doctrine was a statement of United States policy on the activity and rights of powers in the Western Hemisphere during the early to mid 1800s. The doctrine established the United States position in the major world affairs of the time. Around the time of the Napoleonic Wars in the 1820s‚ Mexico‚ Argentina‚ Chile and Colombia all gained their independence
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The History of Clocks | |The history of clocks is very long‚ and there have been many different types of clocks over the centuries. Not all historians agree on the history of the clock. The word clock was first used in the 14th century (about 700 years ago). It comes from the word for bell in Latin ("clocca"). Using the Sun The first way that people could tell the time was by looking at the sun as it crossed the sky. When the sun was directly overhead in the sky‚ it was the middle of the day‚ or
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Chavez English III Block F March 25‚ 2013 Is the Monroe Doctrine still significant? Think of our country as a brick‚ our founding fathers as bricklayers‚ and our governmental documents as the cement. A bricklayer has to make the cement to lie between the bricks so they will stay together. In other words‚ our founding fathers held our country‚ or the bricks‚ by documents‚ the cement. To me one of the most important documents is the Monroe Doctrine. It still has a humongous impact on our society
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learned in the class. Our case study that we picked talked about the clocks and how the society shaped the way of measuring time throughout history. The clock nowadays are technology that has been taken for granted. The focus of this case study is to show the importance of time measurement and how our life nowadays revolves around it. By going through history all the way from using the sun and stars to the development of clocks that neither lose nor gain one second in 200 million years to show how
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PROPELLER CLOCK OBJECTIVE :- In this project‚ our aim is to use PIC or 8051 microcontroller to control a row of LEDs to function it as a clock. ABSTRACT :- The Propeller Clock is an electronic device which has a series of LEDs on board that rotate with the help of a motor to give an illusion of a watching a clock ( Digital or Analogue ). This requires a DC motor which rotates the PCB connected to it with sufficient speed so as to create the illusion. The LEDs are connected to a microcontroller
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"Propeller Clock" Mechanically Scanned LED Clock Seven light emitting diodes spin‚ giving the illusion of numbers in the air An Overview: Top View Side View How this clock works: A motor spins the "propeller"‚ and a small microprocessor keeps track of time and changes the pattern on seven LEDs with exact timing to simulate a 7 by 30 array of LEDs. It is an illusion‚ but it works nicely. To build this clock‚ few things are needed‚ including: 1. Skill with motors and mechanical
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