Kind: captions
Language: en
as an Australian Canadian the Fahrenheit
temperature scale has always seemed a
bit arbitrary to me I mean why does
water freeze at 32° why that integer and
what exactly does zero represent
according to many sources the Fahrenheit
scale was defined by setting 0° equal to
the temperature of an ice salt and water
mixture and 100° 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 fenite
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 a
warrant Fahrenheit met with the mayor of
Copenhagen who happened to be the famous
astronomer ol RoR RoR 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 RoR 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
de and body temperature at 22.5 de. now
this might seem odd until you consider
that RoR wanted the boiling point of
water to be 60° 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 1/8 up
the scale and human body temperature 38
up the scale So at their meeting in 1708
Fahrenheit learned of romer's
temperature scale and adopted it as his
own adjusting it slightly because he
found it inconvenient and inelegant on
account of the 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 his scale by four 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
Bole and hook in which he would have
come across the idea that a one Dee
increase in temperature could correspond
to a specific fractional increase in the
volume of the measuring liquid and today
a 1° fight 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
suggests that this was the case so what
exactly did zero represent on the scales
of Fahrenheit and RoR by many accounts
it's the temperature of a 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 Biz oh 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 uh that was something a
little bit different uh this video was
animated by Marcelo ascani I've got a
link to his channel in the description
you know I became really fascinated with
temperature scales 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 non-fiction
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 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
uh that really changed my thinking about
science when I first read this book 10
years ago so you can check it out by
going to audible.com/veritasium download
it for free and try out the audible
surface so I want to thank Audible for
supporting me and I want to thank you
for watching