Thermometers

or Celsius, Scopes and Scorchers

STORY: DAVID YOUNG IMAGES: 2 x OPEN SOURCE, WEATHER STATION: DAVID YOUNG

“Phew, what a scorcher!” I observed. “It ain’t half hot!” It was one of those occasions when you realise that your conversational skills are lacking. “Aha!” my friend said. (I should explain that he is something of a pedant and therefore has even fewer friends than I have. In fact, even I don’t like him much. He says “Aha!” a lot.)

“Aha!” he repeated. “You imply that it isn’t fifty percent hot. But what does that mean? Half of what? How do you know? Can you measure heat through your senses, or do you have a device on you that can perform the same function?”

“Really I just meant that I’m hot. A hundred percent hot. Like, not cold,” I replied. “But I was merely being conversational.” “Hmmph,” he snorted. “You’re not very good at that, are you?” I quickly decided to investigate the history of the measurement of temperature, for when we next met. Just as quickly, I decided never to meet him again. Here’s what I found. Originally, Galileo Galilei invented something called a thermoscope. He did this between discovering Jupiter’s moons and reinventing the compass. Then he had tea. But you know what they say about all work and no play. Bet he was no fun down the pub. This thermoscope could detect the rise or fall of temperature but did not measure temperature itself. So, not a thermometer. Pull your socks up, Galileo. Oh, sorry – he’s busy disproving heliocentrism. The thermoscope was improved upon by another Italian, Santorio Santorio. Funny thing with 17th century Italians – all seemed to have the same first and last name. Santorio took a simple air thermoscope and applied a scale to it, whereupon it became officially a thermometer. The suffix -scope comes from the Greek for observation, whereas the suffix -meter comes from Greek (or French) for measurement. But I know what you’re thinking. Silly Santorio had neglected to account for variations in air pressure. Spot on, dear reader. The early thermometers fluctuated in their accuracy. In 1654, the Grand Duke of Tuscany, Ferdinand

GALILEO THERMOSCOPE ANDERS CELSIUS

II, (Ferdy to his friends) developed a sealed-glass thermometer, filled with alcohol. The liquid would rise or fall as the temperature made it expand or contract. But even now there was no recognised scale against which to base measurements. Gabriel Fahrenheit, in 1714, produced a thermometer using mercury. Progress in the use of glass allowed more accurate measurements. This was good, but, there was no way to inform others of the temperature. “Is it hot?” they’d ask. “It’s about halfway up my glass bit,” would be the reply. A universal system was needed. Fahrenheit produced a scale in 1724. It was, to be honest, a tad clunky. He set his zero as the point at which a bath of salty water froze. He then set the freezing point of water as 32F, and the body temperature as 96F. The difference of 64 degrees was convenient. Hence the logic. This was later recalibrated so that water’s boiling point would be 180 degrees above 32F. This recalculation now recorded body temperature as 98-ishF. Now I like a good number, but that’s just a mess. Luckily, in 1742 there lived a Swedish astronomer called Anders Celsius. You’ll immediately notice that his Swedish parents haven’t called him Celsius Celsius. Already we’re dealing with a much more systematic way of doing things. He measured two temperatures – the freezing and the boiling points of water, then called one 0 Celsius, and the other 100 Celsius. Whew. Thank Heavens. Common sense prevails. Except… wait for it… he had them upside down, so that, in his original scale, water froze at 100C then boiled at 0C. Jean Pierre Cristin turned the scale upside down

A MODERN WEATHER STATION in 1743 and called his new-ish scale Centigrade. Then, in 1948, Cristin’s scale was renamed (or re-re-named) Celsius. Thermometers thenceforth develop at a exponential speed. Nowadays it doesn’t cost much to have a magnificent digital display on one’s bookcase which will tell you all sorts of stuff that you neither need to know nor understand. “Is it hot out?” my wife recently asked. “Not a clue,” I replied. “But the Hang Seng index has taken a tumble.” Armed with this fulsome history, I almost wish that I could be bothered contacting that pedantic friend (let’s call him Twistleton Twistleton). “It ain’t half hot again,” I’d say. “Aha!” he’d inevitably reply. “But how hot is it really?” “It’s 27 Celsius, or 81 Fahrenheit. Or, using the original Celsius scale, it’s 73. Or, on Galileo’s thermoscope, about an inch and a half.”

replace repair maintain

Glazing Maintenance services

 replacement window and doors  repairs to hinges, handles, locks  misted/broken glass units

www.glazingmaintenanceservices.com

info@glazingmaintenanceservices.com Mervyn J Lynch 020 8529 8020 answerphone / 07973 522 525 direct