18. Argon: More Than Meets The Eye

Today’s element gets called “lazy,” but that’s actually a terrible misnomer.

Featured above: Two honor guards watch over the Declaration of Independence and some high-quality argon.

Show Notes

Good Reads: The Eye of Argon can be read in its entirety here, and I recommend that everyone do so.

Return of Ramsay and Rayleigh: Argon was discovered by the same two guys who discovered neon, actually, a few years earlier. Argon was the easy one to discover, since it makes up one full percent of the Earth’s atmosphere. They would go on to discover krypton and xenon, too, all within a few weeks of each other. But we’ll try to find time for their story when we get to those elements.

Weight Problem: One thing you might have noticed is that, as we traverse the periodic table, each element has weighed more than the last one. This makes sense: The elements are arranged by atomic number, which denotes how many protons are in its nucleus. Usually, the number of neutrons is commensurate with that increase in protons.

Argon, however, weighs more than the next element, potassium. Element 18 has an atomic mass of 39.948, while element 19 has an atomic mass of 39.098. This is because the atomic mass is calculated by averaging the mass of each isotope of an element, by its abundance. There happen to be more isotopes of heavy argon on Earth, and more isotopes of light potassium. It’s a weird quirk, but this means that on average, on Earth, argon weighs more than potassium.

More Of A Treasure Protector: The Declaration of Independence (and Constitution) is protected by more than just bulletproof glass and inert gas. Each night, the documents are lowered into a 50-ton vault that is fireproof, waterproof, and atom-bomb-proof. Two guards keep watch over the documents and can activate the mechanism whenever they think they’re in danger.

I’d Still Rather Eat Them: In 1981, the day after Thanksgiving, Rangaswamy Srinivasan brought his leftovers to work. He had important work to do: Shoot lasers at the bird. You can read more about that here, but the short version is, that led directly to LASIK surgery. (The work done by L’Esperance had more to do with complications from diabetes.)

Really did have a view of central park

Pew Pew: Regarding modern laser weaponry, it’s surprisingly sophisticated and impressive. Take Raytheon’s own High-Energy Laser Weapon System:

In this video, it accurately tracks and quickly destroys a tiny quadcopter. In their own words, this weapon “Identifies, tracks, and defends against enemy missiles, mortars, unmanned vehicles, swarming boat attacks and other ‘close-in’ defense situations. They provide precise, clean, low-cost engagements with near-infinite magazines.”

It’s all fun and games until someone gets hurt, which, actually, is exactly the kind of situation this is intended for.

Store Your Documents In A Cool, Dry, Dark Place: Might I recommend Garth Marenghi’s Darkplace?


Click To Read Transcript


  1. LiveScience, Facts About Argon. Stephanie Pappas, February 20, 2015.
  2. Chemistry World, Argon. John Emsley, May 12, 2010.
  3. Wired, July 4, 1776: Preserving The Declaration. Tony Long, July 2, 2009.
  4. The Edge Of The American West, The Declaration Of Independence And The Constitution In Storage. December 23, 2009.
  5. Professor Mark Csele’s Homebuilt Lasers Page, Argon Ion Lasers.
  6. Columbia University Department Of Ophthalmology, Milestones.
  7. The History Of The Laser, p. 274. Mario Bertolotti, 1999.
  8. Optics & Photonics News, History Of Gas Lasers, Part 1 — Continuous Wave Gas Lasers. Jeff Hecht, January 2010.
  9. Raytheon: Laser Solutions.
  10. Air Power Australia, The Sidewinder Story. Carlo Kopp, 1994, 2005, 2010.

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