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A Crash Course Through Ph O Bs

A Crash Course Through Ph O Bs. also know as the overthrow of the Phlogiston Theory also known as the Chemical Revolution starring Liz Skeete - past Carley Senicki - present with special future guest appearance by Alec Zigar.

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A Crash Course Through Ph O Bs

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  1. A Crash Course Through Ph O Bs also know as the overthrow of the Phlogiston Theory also known as the Chemical Revolution starring Liz Skeete - past Carley Senicki - present with special future guest appearance by Alec Zigar

  2. I love learning about minerals and if I had the right materials I could totally make myself invisible (Bryson, 2012) Our story begins in 1667 with J.J. Becher who wrote this book on minerals which lead to the discovery of Why do things burn? Why do metals rust? Ph Phlogiston

  3. Ph Phlogiston What is this that you speak of? Pronounced “FLAW-GEST-ON”…I think…and it means “burning up” in Greek • The “Phlogiston Theory” was a widely accepted conceptual framework used to explain many chemical phenomena in the 18th century, such as what happens when something burns.

  4. Flammable materials contain a special colourless substance called “phlogiston”, which is released during combustion. • When “common air” is mixed with “phlogiston” is becomes “fixed air”, which is fatal to any animal breathing it. • Breathing, in particular exhalation, was also thought of as a way to take phlogiston out of the body.

  5. A typical test for the presence of phlogiston was to place a mouse in a container and measure how long it would take to die.

  6. Exciting Demo Time I wonder what’s going to happen • Take a lit candle. • Cover the candle with a beaker. • Wait… • The flame dims and goes out.

  7. What happened? • When a candle is burning in an enclosed space, the air can only absorb so much phlogiston and the air will eventually become saturated. • Now when the air has become completely “phlogisticated”, it is also said to be “fixed air” that is no longer able to support combustion. That is why the flame goes out.

  8. #TBT to EDUC711 Then along came Joseph Priestly. Even though Priestly was a strong supporter of the phlogiston theory, his experimentation was highly influential in the theory’s eventual overthrow. Priestley discovered a gas that promoted combustion and respiration far better than “common air”. Even though Priestly effectively discovered oxygen, he still referred to it as “dephlogisticated air”. The mouse, when exposed to this air, didn’t die. YAY!!!

  9. Why does this story matter today? • This Harvard Case Study explores the nature of science with its inquiry, experimentation, observation, and challenges. • The history of scientific exploration shows that scientific discoveries are often the product of lots of time as several scientists build on each other’s ideas. • It also may require time for scientists as well as the public to come to terms with new discoveries. • Phlogiston seems silly now but it was the best explanation at that time. Remember, all models are wrong but some are useful.

  10. Priestly might have been on to something… Our story continues with the “antiphlogistic” ideas of Antoine Lavoisier and his effective discovery of oxygen and oxidation…and there’s time for another exciting demo (but this one is actually exciting)

  11. Bryson, B. (2012). A Short History of Nearly Everything, London: Black Swan. • Conant, J. B. (1956). The Overthrow of the Phlogiston Theory: Harvard Case Studies in Experimental Science, Case 2. Cambridge MA.: Harvard University Press.

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