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Henry Cavendish (1731 – 1810) PowerPoint Presentation
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Henry Cavendish (1731 – 1810)

Henry Cavendish (1731 – 1810)

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Henry Cavendish (1731 – 1810)

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  1. Henry Cavendish(1731 – 1810) The Weighing of the Earth

  2. Personal Life • As the grandson of the Second Duke of Devonshire, he was considered nobility • He attended Cambridge University from 1749 – 1753, but left without earning a degree • His inherited fortune enabled him to pursue scientific studies • Viewed as solitary and eccentric, he had no friends apart from his family • Asperger’s Syndrome – account for his unusual shyness • Prohibited from publishing his work until James Clerk Maxwell looked through his papers • Saw credit to most his discoveries had been given to others: • Richter’s Law of Reciprocal Proportions, Ohm’s Law, Dalton’s Law of Partial Pressures

  3. Discovery of Hydrogen • In 1766, In a paper called On Factitious Airs Cavendish addresses a “inflammable air” which forms water as a result of combustion. • Antoine Lavoisier later reproduced the experiment giving Cavendish’s element the name Hydrogen

  4. Composition of Atmosphere • Established an accurate composition of the atmosphere • ~79% “phlogisticated” air (nitrogen and argon) • ~21% “dephlogisticated” air (oxygen)

  5. Weighing of Earth • Cavendish used an torsion balance apparatus to complete the experiment in 1797 • Originally created by John Mitchell who died before he could put it to use • Apparatus sent in crates to Cavendish • The apparatus consisted of a torsion balance to measure the gravitational attraction between two 350 pound lead spheres • Consisted of a 6-ft wooden rod with metal spheres attached to each end, hanging from a wire which twisted as a result of the gravitation attraction between them • Wind proof room • Torsion of wire measure by the telescope

  6. Gravitation Constant and Mass of Earth • With G, he could easily calculate the earth’s mass to be 5.9725 billion trillion tons (his estimate was 1% off)