Brrr… It’s verrry cold in Minnesota. This morning, the air temperature in the neighboring suburb of Eden Prairie is -21 degrees Fahrenheit. On the metric temperature scale used by all scientists and by the general public in nearly every country in the world, the temperature is -29 degrees Celsius. [Only the United States, Liberia, and Burma (Myanmar) haven’t yet switched to the metric scale for measurement.]

When the temperature gets this low, I start surfing the web pages of the National Weather Service so I can find the lowest official temperature that I can honestly claim to others. For example, this morning’s low temperature in the Twin Cities metropolitan area ranged from -21 (Eden Prairie, Flying Cloud Airport) to – 18 (Bloomington, Minneapolis/St. Paul International Airport) to -24 (Lakeville, Airlake Airport).

My 17-year-old son must have inherited the same cold-seeking gene.  He told me yesterday that he had been roaming the internet to look at temperatures; he reported that our temperatures in Minnesota were the same as those at the South Pole (where it is currently summer).

The same sort of cold competition can be found in northern Minnesota, where three different towns (International Falls, Tower, and Embarrass) all claim to be the coldest place in the “lower 48.” This morning, the temperature in International Falls was -40. The lowest recorded temperature in Minnesota was -60 (Tower, MN, February 2, 1996).

During that extremely cold winter of 1996, the temperature here in Minneapolis dipped to -32 degrees Fahrenheit. I was thrilled. I bought several thermometers to keep outside on the deck, so I could monitor the cold. As long as it was going to be that frigid, I really wanted the temperature to plunge to -40 degrees. For me, that’s a magical temperature, for several reasons.

First, it’s the one temperature at which the Fahrenheit and Celsius scales coincide. -40 degrees Fahrenheit is also -40 degrees Celsius. At that particular temperature, the residents of the United States are international citizens in the world of measurement. Like the early Christians on Pentecost, we can understand each others’ languages.

And there’s a second reason I’m a big fan of -40 degrees. At just about this temperature, mercury will freeze solid. The freezing point of mercury, at standard atmospheric pressure, is -38.83 °C or -37.89 °F. If you’re using a mercury thermometer (not as common today as they used to be), it stops working at this temperature.  You can’t ever reach -40 on a mercury thermometer.

Just about a year ago, I was thinking about even colder temperatures, while working on a project for public television. My assignment was to prepare a timeline that showed the progress of low-temperature science, a timeline that would accompany the “NOVA” television program, “Absolute Zero. Here’s the hyperlink for my timeline contribution to the project, Milestones in Cold Research.

Here are several fun temperature facts I learned while working on that timeline project:

• The thermoscope (a predecessor to today’s thermometers) was invented by Galileo Galilei in the 1590s. The first modern-style, sealed-glass thermometer was invented in 1654.

• The world’s first home air conditioner was installed in Minneapolis, Minnesota—in 1914 by a man named Charles Gates. The machine, built by Willis Carrier, was almost 7 feet high, 6 feet wide, and 20 feet long. (Of all places to install the first home air conditioner, why in Minnesota?)

• At extremely low temperatures (20 nanokelvin or 0.00000002 degrees above absolute zero), a new form of matter can be observed. Called the Bose-Einstein condensate, it was the subject of the Nobel Prize in Physics in 2001.

Now that I’ve spent so much time thinking and writing about cold, I think I’ll stay inside and read a good book in front of my fire.   I’ll probably choose a book about the cold–perhaps the famous short story by Jack London, “To Build a Fire,” about a man and his dog trying to survive in the Yukon in temperatures of 75 degrees below zero.

Published in: on January 13, 2009 at 8:31 am  Comments (3)  

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3 CommentsLeave a comment

  1. Ooh, I didn’t know that about -40 degrees. I too urge the temperature to keep dipping when it gets that low. If I’m going to freeze, I should at least get something to brag about. Same with excessive snow.

  2. It’s even colder this morning. The air temperature is -27 degrees, and the wind chill is -41 degrees. Those are good bragging numbers. I’m glad my car started this morning; the battery was pretty darn sluggish.

  3. We put our plants in the gaarge before we went camping so they survived. I was too busy to put them in the ground so it pays to procrastinate ;)Our camping trip in Goderich was a bit cold and we had frost on out tent Sunday night, but we survived in our sleeping bags that are good to -7.

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