Franklin. Benjamin, experiment

Benjamin Franklin s experiment is mentioned in the opening paragraphs of this chapter. Estimate, from his results, an approximate value for Avogadro s number make your calculation clear. The answer is a little off explain whether more accurate measurements on Franklin s part would have helped. 

An engaging discussion of the history of Benjamin Franklin s experiment and a relatively nontechnical treatment of monolayers and bilayers of surfactants and their implications to biochemistry and biology are presented by Tanford, a pioneer of what is known as the hydrophobic effect and the biological applications of mono- and multilayers (Tanford 1989). Almost all of the material discussed in this highly readable volume is relevant to the focus of this chapter. 

Benjamin Franklin, author and renowned statesman, was also an inventor and a scientist. Every schoolchild knows of Franklin s experiment with a kite and a key, demonstrating that lightning is electricity. Less well known is that his measurement of the extent to which oil spreads on water makes possible a simple estimate of molecular size and Avogadro s number. 

One of the earliest studies of insoluble films was conducted by Benjamin Franklin in 1765 on a pond in Clapham Common in London. Surprisingly Franklin s experiment was sufficiently controlled to establish that olive oil formed a film of monolayer thickness (quoted... 

I. Bernard Cohen (ed.), "Benjamin Franklin s Experiments" (Harvard University Press, Cambridge, MA, 1941). 

Experimental Researches and Observations on Electricity made at Philadelphia and communicated in several letters to Mr. Collinson in LondoUy London, 1751 1752 (with Second Communication)y 1754 (with Third Communication) New Edition of the Whole, 4°, 1766 with Additions, 1769,117 f. The Complete Works, London, 1806, i, 165-440 new ed. by I. B. Cohen, Benjamin Franklin s Experiments, Cambridge, Mass., 1941. The letters run from 1747 to 1754. 

In 1765, Benjamin Franklin described experiments that he had done on Clapham pond near London (see Section 1.3). He observed that a teaspoon of oil (2.5 cm ) placed on the water surface would cahn the surface up to 3000 m. Use this to estimate the size of a molecule (assume that the oil forms a mono-layer). Assuming that the oil was oleic acid with a molar mass of 282 g moL and a density of 0.895 gcm, calculate the thickness of the layer and the area per molecule. Compare the results with the dimensions of an oleic acid molecule. 

Franklin, Benjamin (1706-90) was a Philadelphia printer, self-taught scientist, sage, inventor, author, revolutionary, and diplomat. He was, by age and experience, the senior member of the committee that charged Jefferson with the task of drafting the Declaration of independence. Eleven years later the elderly Franklin helped draft the new United States Constitution. In the interim he served as American ambassador to France, where he was lionized as the epitome of American openness and candor. His contributions to American letters include his Autobiography and Poor Richard s Almanac. 

One of Benjamin Franklin s experiments was to pour olive oil (oleic acid CH3(CH2)tCH=CH(CH2)7COOH), density = 0.895 g mL i) on the surface of a pond in London and observe the oil forming a surface film. If the pond was 0.50 ac in area and 1.0 teaspoons of oil were used, calculate the area of each oleic acid molecule assuming a monolayer film was formed. 

Fortunately for a poor, would-be chemist like Leblanc, France s aristocratic passion for the physical sciences crossed economic, social, and political borders. Intellectuals such as Rousseau and Diderot cultivated the sciences with enthusiasm and compiled encyclopedias and dictionaries of natural substances. Local academies and institutes in the far-flung provinces sponsored chemical studies. Crowds flocked to hear chemists lecture and to watch their flashy laboratory demonstrations. Even the future revolutionary, Jean-Paul Marat, experimented with fire, electricity, and light and tried—in vain—to become a member of the Royal Academy of Sciences. In America, Benjamin Franklin abandoned his printing and publishing business for physics, and in England his friend Jane Marcet wrote Mrs Marcet s Conversations in Chemistry for women and working-class men. 

If Benjamin Franklin hadn t noticed how the water changed behind ships as they sailed, he wouldn t have experimented with oil and water. If you notice what s going on around you, you ll see all kinds of things to investigate and explore. 

Lord Charles Cavendish might not have been wealthy, but he was a natural philosopher and experienced experimentalist. Indeed his research on heat, electricity, and magnetism earned him praise from Benjamin Franklin. Henry must have learned a lot from his father, because he, too, became a meticulous experimenter. Some of Henry s experiments in physics and most of his chemical experiments were performed while he was still living under his father s roof. 

In December 1765 Priestley journeyed to London, hoping to make the acquaintance of some of his fellow British scientists. By this time, he had attained some prominence as the author of a number of textbooks that were based on the courses he taught at his school. While in London, he performed his first experiments, some of them under the direction of Benjamin Franklin, who was in London at the time as a representative of the government of Pennsylvania. 

Not long after this meeting with Benjamin Franklin, Priestley accepted a pastorate at Leeds. Since the parsonage happened to be located next door to the Jakes and Nell Brewery, the Reverend Mr. Priestley had a convenient source of fixed air for his experiments. He soon discovered the pleasant taste of water charged with this gas, and recommended the refreshing beverage to his friends. Dr. William Brown-rigg had previously made the same discovery (22, 47). 

On 1752, Benjamin Franklin (1706—1790) learned from experiments with... 

PRIESTLEY, JOSEPH (1733-1804). Priestley was an English chemist who researched relationships among plants, air, and animals. After meeting Benjamin Franklin he became interested in science and the two men became lifelong friends. Priestley started doing chemical experiments as a hobby, but it soon became a passion. He had little scientific education but his observations were very keen. 

In 1774 Benjamin Franklin recounted his first experiences with surfactants to the British Royal Society. 

Benjamin Franklin studied electricity in the mid-1700s. He developed the concept of positive and negative electrical charges. His most famous experiment showed that lightning is an electrical process. 

Benjamin Franklin and Mme. Marie Curie were experimental physicists. Isaac Newton and Albert Einstein were theoretical physicists, perhaps the greatest. In the earlier days, the tools, both experimental and mathematical, were so simple that a single man or woman could become skilled in the use of both kinds. Isaac Newton not only made the thrilling experiment of breaking sunlight into colors with a prism, but actually invented for his own use one of the most useful forms of mathematics, the calculus. Franklin contributed to electrical theory. Nowadays some of the tools are so complex that few physicists are versatile enough to become masters of them all. 

International recognition Many scientists held Lavoisier in high esteem. Benjamin Franklin made a point to observe experiments by Lavoisier when he was in France soliciting support for the cause of the American Revolution. Lavoisier s experiments were also followed closely by Thomas Jefferson. 

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