Chemistry

Brilliant low-tech soil moisture sensor

Brilliant low-tech soil moisture sensor

Two galvanized nails set in a plug of plaster-of-Paris. That’s it. The Cheap Vegetable Gardener, who created the sensor for an automated grow box project, explains:

Technically a gypsum block measures soil water tension. When the gypsum block is dry it is not possible for electricity to pass between the probes, essentially making the probe an insulator with infinite resistance. As water is added to the problem more electrons can pass between the probes effectively reducing the amount of resistance between the problem to the point when it is fully saturated where the probe has virtually zero resistance. By using this range of values you can determine the amount of water than exists in your soil.

[via Hack a Day]

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Element 112 officially “Copernicium”

Element 112 officially “Copernicium”

Admittedly, if you’re not a chemist or physicist, you may find this post as boring as dirt. (Please forgive the simile, microbiologists. I know dirt is actually fascinating.) Then again, it’s not everyday a new element is added to the periodic table.

The latest addition, number 112, was discovered on February, 9th, 1996 at 10:37 PM by a team under Professor Sigurd Hofmann at the GSI Helmholtzzentrum für Schwerionenforschung (Center for Heavy Ion Research) in Darmstadt, Germany, who confirmed its existence by observing a characteristic “decay chain” of radioisotopes (illustrated above) that could only have originated with element 112.

Just a couple weeks ago, on February 19, that discovery was officially confirmed by the International Union of Pure and Applied Chemistry (IUPAC), who accepted the GSI team’s recommendation of the name “Copernicium” in honor, naturally, of Nicolaus Copernicus, whom most will recall as the first scientist to stand up and declare that the earth revolves around the sun, rather than the other way ’round. The new two-letter symbol is “Cn.”

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Petition to establish “hella-” as SI prefix for octillion

Petition to establish “hella-” as SI prefix for octillion

Thanks to the prodigious growth of computer storage media over the past couple of decades, most people have a pretty good command of the metric (SI) prefixes for big numbers: a kilobyte is a thousand bytes, a megabyte is a million, a gigabyte is a billion, and a terabyte is a trillion. Some folks are already making noises about “petabyte”–or one quadrillion byte–storage media. After that comes “exabyte,” which, of course, would be a quintillion bytes. And beyond that you get into “Marx brothers” country. More than one wag has suggested that the as-yet-unnamed metric prefix to denote one octillion somethings-or-other should be “groucho” or “harpo.”

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Maker Birthdays: Linus Pauling

Maker Birthdays: Linus Pauling

Yesterday, February 28, 2010, Linus Carl Pauling would’ve been 109 years old. And we’d all be better off he were still with us since, by all accounts, even a doddering Pauling could’ve run rings around most folks intellectually. One of four human beings ever to have been awarded multiple Nobel Prizes, and the only one ever to have won both the Nobel Prize for Chemistry (1954) and the Nobel Peace Prize (1962). His 1939 Nature of the Chemical Bond remains one of the most influential chemistry texts ever published, and his 1947 General Chemistry, available in its classic 3rd edition through Dover Publications for a song, remains one of the best-written and most readable introductions to the subject. The Nobel Peace Prize was awarded for his instrumental role in scientific activism to end above-ground nuclear weapons testing. A complete list of Pauling’s accolades could, and has, filled several books, but I can’t resist mentioning, in closing, that geek ubermensch Linus Torvalds is reportedly named after him.

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Professor destroys laptop with liquid nitrogen

Physics professor Kieran Mullen of OU apparently has a hard-and-fast rule against laptops in class. To drive the point home, he staged a public execution of one by freezing it in liquid nitrogen and smashing it against the floor, where its broken remains were left as a warning to others. Of course the whole thing is staged and the laptop in question was old and worthless, but hey, any excuse to freeze stuff with LN2 is OK with me.

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Superconductor levitates around circular supermagnet track

High-temperature superconductor (Yttrium barium copper oxide) floating in the magnetic field of Neodymium magnets. This phenomenon is called the Meißner-Ochsenfeld-Effect and was discovered in 1933. The superconductor has to be cooled with liquid nitrogen which has a temperature of 77 K or −196 °C. If it is placed in a strong magnetic field it remains in its position. It also works if you turn the track upside down

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