Inside: Cold temperatures and hot temperatures, measuring temperatures is possible thanks to Anders Celcius and Daniel Fahrenheit.

I have harped on about weather and temperature for the past few posts.  I’ve been fixated on very cold temperatures lately as our corner of the world has experienced some very cold temperatures this past week.  I thought I’d present some history behind the science of taking temperature. In doing so, I’ve shared one relevant episode of a video series I used a lot in my early days of teaching, Eureka.  Grade nine and ten general science always contained a physics section or two. These videos were a great tool for those topics.  The science is basic but the main character is endearing – he’s a little like Beaker from the Muppets fame.  I hope you enjoy at least part of it.

Now for the science history lesson.  The first thermometer called a thermoscope was invented in 1612 by Santorio Santorio.  He also applied a numerical scale to his temperature measuring device which was the precursor to the thermometer.

Daniel Gabriel Fahrenheit invented the alcohol thermometer for measuring temperature in 1709 and followed that by inventing the mercury thermometer in 1714.

op unknown, Public domain, via Wiki Commons

Daniel Fahrenheit: op unknown, Public domain, via Wiki Commons

Daniel Fahrenheit also developed the measurement scale which bears his name.  He based his zero point on the temperature of brine using a mixture of ice, water, and ammonium chloride.  This frigorific mixture stabilizes its temperature at 0ºF.  The second point, he labeled 100ºF was the temperature reached when the thermometer was placed in the mouth of his wife.

Anders Celsius did not invent a thermometer but he did devise the measurement scale, bearing his name, that would be adopted by an international conference on weights and measures.  Anders was a

Olof Arenius, CC-BY-SA-3.0, via Wiki Commons

Olof Arenius, CC-BY-SA-3.0, via Wiki Commons

Swedish scientist who came up with his scale in 1742.  He used the freezing point and boiling point of water as his upper and lower base points.  He assigned 0ºC as the freezing point of water and 100ºC as the boiling point of water.

If you watch the video to its end you will see a simplified explanation of the work of Celsius.  Although his scale was accepted as the scientific standard, the Fahrenheit scale is still used exclusively in the United States and without a doubt, it was the creative genius of Daniel Fahrenheit that led to this accurate tool for measuring temperature.

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