Placeholder Image

字幕表 動画を再生する

  • As an Australian Canadian

  • the Fahrenheit temperature scale has always seemed a bit arbitrary to me.

  • I mean why does water freezes at 32 degrees?

  • Why that integer and what exactly does 0 represent?

  • According to many sources

  • the Fahrenheit scale was defined by setting 0 degrees

  • equal to the temperature of the ice salt and water mixture

  • And a hundred degrees being roughly equal to human body temperature.

  • But that isn't true.

  • The real story is much more interesting and scientific.

  • August 14th, 1701 was almost certainly the worst day

  • in the life of 15 year-old Daniel Gabriel Fahrenheit.

  • On that day, both of his parents died suddenly from mushroom poisoning.

  • And he was sent from Poland where he lived

  • to Amsterdam to become an apprentice bookkeeper.

  • But Fahrenheit couldn't stand his apprenticeship and

  • ran away so many times that his employer put out a warrant for his arrest.

  • Traveling from city to city around Europe,

  • he became fascinated with scientific instruments

  • and in particular, thermometers.

  • In 1708, possibly seeking help with the warrant,

  • Fahrenheit met with the mayor of Copenhagen,

  • who happened to be the famous astronomer Olemer.

  • mer is known for observing the eclipses of Jupiter's moons

  • and realizing that variations in the timing of those eclipses

  • was caused by the time it took light to reach Earth.

  • In other words, he found a way

  • to accurately measure the finite speed of light.

  • But, more pertinent to this story,

  • in 1702, Rømer was housebound after breaking his leg.

  • And to pass the time, he devised a brand-new temperature scale

  • with the freezing point of water at 7.5 degrees

  • and body temperature at 22.5 degrees.

  • Now, this might seem odd until you consider thatmer wanted

  • the boiling point of water to be 60 degrees.

  • As an astronomer, he had experience dividing things by 60.

  • So if you take this scale,

  • divide it in half, in half again and in half once more,

  • you find the freezing point of water one eighth up the scale,

  • and human body temperature three eighth up the scale.

  • So at their meeting in 1708

  • Fahrenheit learned ofmer's temperature scale and adopted it as his own,

  • adjusting it slightly because he found it

  • "inconvenient and inelegant on account of fractional numbers".

  • So he scaled them up to 8 and 24.

  • And this is the original Fahrenheit scale.

  • He produced thermometers for some time using this scale.

  • But then at some later point,

  • Fahrenheit multiplied all numbers on the scale by 4

  • setting freezing point to the now-familiar 32 and body temperature to 96.

  • It's unclear exactly why he did this.

  • He may just have wanted finer precision in his measurements.

  • But I think there was a better reason.

  • You see, Fahrenheit was an excellent instrument maker.

  • His thermometers agreed with each other precisely

  • at a time when that was unheard of.

  • He pioneered the use of mercury as a measuring liquid,

  • which has the benefit of a much higher boiling point than the alcohol

  • used in most other thermometers at the time.

  • And for these accomplishments

  • he was inducted into the British Royal Society.

  • And we know that he read the works of Newton, Boyle, and Hook,

  • in which he would have come across the idea

  • that one degree increase in temperature could correspond to

  • a specific fractional increase in the volume of the measuring liquid.

  • And today, a one degree Fahrenheit increase in temperature

  • increases the volume of mercury by exactly one part in 10,000.

  • Is this just a coincidence?

  • Well, we'll probably never know for sure because

  • as an instrument maker Fahrenheit was very secretive about his methods.

  • But I think the data strongly suggest that this was the case.

  • So, what exactly did zero represent on the scales of Fahrenheit, andmer?

  • By many accounts, it's the temperature of salt ice and water mixture.

  • The only problem is there are different descriptions of these mixtures

  • And none of them actually produces the temperature they're supposed to.

  • More likely, I think they picked the coldest temperature in winter

  • set that as zero

  • and later used ice and brine to calibrate new thermometers.

  • In his day, the Fahrenheit thermometer was the best you could get.

  • But now his scale is only used regularly in the Cayman Islands,

  • Bahamas, Belizeoh, and the United States of America.

  • So maybe it's time we all adopted the global scale of temperature:

  • Celsius, which by the way, wasn't invented by Celsius at all.

  • Hey! So that was something a little bit different.

  • This video was animated by Marcello Ascani.

  • I've got a link to his channel in the description.

  • You know, I became really fascinated with temperature scale

  • after I saw the original Celsius thermometer.

  • You can see that video here.

  • Now, this video was supported in part by viewers like you on Patreon,

  • and by audible.com,

  • a leading provider of audiobooks with hundreds of thousands of titles in

  • all areas of literature,

  • including fiction nonfiction and periodicals.

  • And for viewers of this channel,

  • Audible offers a free 30-day trial

  • where you can download any book of your choosing.

  • Just go to audible.com/veritasium.

  • And I have a book that I would recommend to you.

  • It is called The Structure of Scientific Revolutions by Thomas S. Kuhn.

  • This is a classic in the history and philosophy of science.

  • And it'll make you see science in a different way

  • because it shows us that science is not just one process

  • but there are actually revolutions that take place

  • when big discoveries are made.

  • And that really changed my thinking about science

  • when I first read this book ten years ago.

  • So you can check it out by going to audible.com/veritasium

  • downloaded for free and try out the Audible service.

  • I want to thank Audible for supporting me and I want to thank you for watching.

As an Australian Canadian

字幕と単語

動画の操作 ここで「動画」の調整と「字幕」の表示を設定することができます

B1 中級

華氏は? (What the Fahrenheit?!)

  • 613 46
    Mike NiKao-Kusata に公開 2021 年 01 月 14 日
動画の中の単語