00:00We all learn very early on in our lives about temperature and how it's measured.
00:06Now, most of us are familiar with the Celsius scale, the one used by 99% of countries on Earth.
00:13But there's always that one country that has to be different.
00:17Thus, in the United States of America, temperature is instead measured in freedom units,
00:24or as some people call them, degrees Fahrenheit.
00:27Now, setting aside the endless debate over which scale is superior, which is obviously Celsius,
00:34this does beg the question, what scale did people use before Fahrenheit and Celsius came along?
00:42Before we answer that question, it's worth noting that people measured temperature long before they figured out a scale with
00:49which to compare their measurements.
00:51We know that in Ptolemaic Egypt, a mathematician called Philo observed that air expanded when it was heated.
00:59He built a tube partially filled with water, and he could tell whether the air was getting warmer or colder
01:06based on how far up the tube the water reached.
01:09Obviously, this knowledge wasn't all that useful at the time, so Philo's invention went mostly unnoticed.
01:17Only after the Romans had conquered Egypt did it again resurface, with minor improvements from our friend Hero of Alexandria.
01:26Now, these devices weren't true thermometers, and not just because they lacked a scale.
01:32Due to their reliance on air, their measurements changed with air pressure.
01:37Essentially, they were unintentional barometers.
01:41Today, we call these devices thermoscopes.
01:44Sounds like a brand of underwear, actually.
01:46I need to slide on my trusty thermoscopes.
01:50Oh.
01:51And they would remain the only items on the market for over a thousand years.
01:56Only in the wake of the Renaissance did various inventors rediscover these ancient thermoscopes.
02:03Available in Saturn, Black, and Hot Pink.
02:06And adapt them to their own needs.
02:09Oh, blimey!
02:11Look at that thermoscope!
02:13Hoo, hoo, hoo!
02:14That's raising my temperature, that is.
02:17For example, an Italian physician called Sanctorius wanted to measure the body temperature of his patients.
02:24So, he had them breathe into a small glass tube with evenly spaced marks, and then placed it upside down
02:31in water.
02:33I'll be just a moment.
02:34In the meantime, here, have a spicy meat of all.
02:37It was the exact same concept as Philo's thermoscope, but now applied to medicine.
02:44Later manuscripts of his show the device fully sealed, and with a refined scale, that has one extreme at the
02:51temperature of snow, and the other at that of a burning candle.
02:55So, these two innovations combined would make his device the first real thermometer.
03:01But again, there's a lot of other contenders here.
03:04A Dutch engineer, famous for inventing the submarine, also had a need to measure temperature for his chicken incubator, as
03:12it happens.
03:13It's a very poultry idea.
03:16Perhaps not as high on the pecking order.
03:19It's a joke with pecking poultry.
03:22His device notably used alcohol and mercury instead of water, and it too was sealed.
03:30So perhaps he should be credited as the inventor of the thermometer, seeing as he created his a full five
03:37years earlier than Sanctorius.
03:39Another notable inventor was Sir Isaac Newton.
03:43He had gotten really into alchemy in his later years after losing all his money betting on stocks.
03:50He truly was ahead of his time.
03:53Now, in order to turn lead into gold, Newton needed to accurately measure temperature, and for that he created his
04:01own temperature scale.
04:02In a stunning show of providence, he put the freezing point of water at zero degrees.
04:09He then added another 17 reference points, mostly the melting points of various metals, but also a few hilariously vague
04:18ones, like the greatest heat of a bath,
04:22which one can endure for some time when the hand is dipped in and is kept in constant movement.
04:28That temperature is 14 degrees, according to Newton's scale, and just 3 degrees higher is the same description, but with
04:39the hand kept still.
04:41Newton, of course, wasn't particularly interested in thermometry itself, so he never tried to popularize his scale.
04:48And this is where we get to our famous acquaintance, Daniel Fahrenheit.
04:53Unlike Newton, Fahrenheit was absolutely obsessed with thermometers, and he spent most of his life working on his scale.
05:02At zero degrees, he set the temperature of a mix of ice, water, and ammonium chloride.
05:09Now, that might sound like a very weird mixture to use as your base, but it's actually quite brilliant.
05:15And to understand why, we're going on a short trip into the wonderful world of physics.
05:22Huzzah!
05:24Fahrenheit's particular mixture has a very useful property.
05:28Regardless of what temperature the components are at when mixed, they'll always arrive at the same equilibrium temperature.
05:36In physics, this is known as a frigorific mixture, and it's perfect for calibrating thermometers,
05:42or for describing something that is good, but also has a bad side effect.
05:48Friggerific!
05:49Interestingly enough, Fahrenheit wasn't the one who discovered this property.
05:55He copied it from another temperature scale invented by a Danish astronomer, Ole Römer.
06:02Like Newton, Römer just wasn't that into thermometry.
06:06He preferred gazing at the night sky, and is in fact famous for making the first accurate measure of the
06:14speed of light.
06:15It is thanks to Römer's magical mixture that Fahrenheit was able to produce consistently accurate thermometers,
06:23and that's why his scale became so popular.
06:25Only later did our lord and saviour, Anders Celsius, come along to bless us with his superior scale.
06:34But, as I said, that's a topic for another time.
06:38Unfortunately, that's all for now, my dear viewers.
06:42I hope you've enjoyed our brief thermometric adventure.
06:45Rest assured that we'll eventually make a follow-up video,
06:50although I provide absolutely no guarantees as to how or when that might happen.
06:56Conditions apply. See store for details.
06:58In the meantime, please remember to subscribe,
07:00and continue contributing to our courteous cause by joining the righteous ranks of our patrons.
07:07Anyhow, keep an eye out two weeks from now for the next carefully calibrated episode of SideQuest.
07:15I can feel the temperature rising.
07:18There's a comment on the content. Where's the button?
Comments