Saturday Science Quest!

quest to explore science continues this week with some interesting facts about temperature!

What is absolute zero?

It is snowing outside, Jack Frost is nipping at your toes, and as your teeth are chattering you can't help but think, 'Where is all this global warming we were promised?'.

Yes, it's winter and it is cold outside. But how cold can cold it get?

Absolute zero, that's how cold!

Absolute zero is a temperature 273 degrees Celsius (459 degrees Fahrenheit – see that puts a bit of prospective on your chilly morning scraping ice off of your car windscreen before work) below freezing. Nothing can ever be colder than absolute zero, just as it is impossible to have less than no thickness. The colder something is the harder it is to cool it any further. This is the bottom of the scientific temperature scale, or zero degrees Kelvin. This way of measuring temperature is named after Lord William Kelvin who devised the theory behind the unit in the middle of the 19th century.

Here are some very low temperature facts:

The average temperature of the universe due to cosmic microwave background radiation today is 2.73 K.

Absolute zero cannot be achieved artificially, although it is possible to reach temperatures close to it through the use of cryocoolers. The use of laser cooling has produced temperatures less than a billionth of a kelvin. At very low temperatures in the vicinity of absolute zero, matter exhibits many unusual properties, including superconductivity, super fluidity, and Bose–Einstein condensation. To study such phenomena, scientists have worked to obtain even lower temperatures.

The rapid expansion of gases leaving the Boomerang Nebula causes the lowest observed temperature outside a laboratory.

In February 2003, the Boomerang Nebula was observed to have been releasing gases at a speed of 500,000 km/h (over 300,000 mph) for the last 1,500 years. This has cooled it down to approximately 1 K, as deduced by astronomical observation, which is the lowest natural temperature ever recorded.

The current world record was set in 1999 at 100 picokelvins (pK), or 0.000 000 000 1 of a Kelvin, by cooling the nuclear spins in a piece of rhodium metal.

In November 2000, nuclear spin temperatures below 100 pK were reported for an experiment at the Helsinki University of Technology's Low Temperature Lab. However, this was the temperature of one particular degree of freedom – a quantum property called nuclear spin – not the overall average thermodynamic temperature for all possible degrees in freedom.

In September 2009 Scientists identify coldest place on earth. The site, known simply as Ridge A, is nearly 14,000 metres high and is located deep within the Antarctic Plateau. It has an average winter temperature of minus 94 degrees Fahrenheit (minus 70 degrees Celsius) and is so remote that it is thought that no human has ever set foot there.

In December 1997 absolute zero was achieved in the living room of my girlfriend of the time parent's house as the announcement was made that she was in fact going out with the long haired guy with the nose ring and tattoos stood next to her.*

*This last fact, although true, has yet to be scientifically proven and therefore should be ignored in any science studies until such time that the speculation on behalf of the participants of the study can be substantiated.

sourses: Tacye Phillipson, Science curator, NMS and Wikipedia


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