The Smell Before the Storm

I still remember one of the last Discovery Channel-style epiphany that occurred to me before I overdosed on Physics and the mere mention of the word started sending me into irrepressible fits of maniacal laughter:

While studying the effect of high-voltage electrical current on molecular geometry, our professor mentioned in passing that this was, in essence, what happened in the skies before (and during) your typical thunderstorm: oxygen molecules (O2) would get dissociated into unstable atomic oxygen that would recombine with more O2 to make ozone (O3). Ozone being much more dense than molecular oxygen then proceeds to fall straight to the ground where it reaches the unsuspecting layman’s nostrils.

So that lovely and unique smell that fills the air just before a Summer storm like right now is the smell of ozone.

Science is, indeed, a wonderful thing.

Update: Scott’s insightful contribution and some more amusing scientific facts about Ozone, in the comment section.

4 comments

  1. Ha,

    I was expecting that one (no really, I was).

    Well, to be perfectly honest, I did consider the case of the ozone layer (formed by UV dissociation) and wondered briefly why “it was not falling to the ground” like pre-storm ozone (whose density is about 1.5 that of molecular oxygen at same temperature). But chose to ignore the problem altogether, since I have enough of this awful “science” crap in my textbooks as it is at the moment (Personal announcement: Heinsenberg: cursed be on thee and thy descendants for generations to come, I hate you. End of personal announcement).

    However, lizard brain did provide some kind of reassuring answer along the line of:
    “Stratospheric ozone doesn’t fall for pretty much the same reason as satellites do not fall: Probably involves a balance between centrifugal force and gravity which is much less important at such altitude.”
    Upon further reflection, I’d add factors such as temperature (Ozone molecules ought to be warmer since they absorb the bulk of high-energy UV rays).
    Why there’s a “layer” would seem to corroborate my admittedly simplistic balance-of-force suggestion: such a balance would only be valid at a certain range of altitude (no idea why it would be a range and not a very exact altitude of x meters, but it’s physics, so we can *always* expect results to be crude and approximative)…

    If you have *the* answer though, please by all means go ahead, I’m too lazy for even extensive googling today, and the links you included is dead unfortunately.

    > It’s also the sweet smell that surrounds high voltage electronics. Mmm, ozone…

    Yea, laser printers or copiers in particular…

    And for our ozone-loving friends out there.

    Extra Bonus 1: the origin of the word.
    Ozone was made in the 19th century from the greek word οζειν (ozein): to smell…

    Extra Bonus 2: “Because of it’s strong odour destroying properties, ozone is often used to freshen the air in public facilities and can be used to reduce the smell of smoke damage in a building. […] It’s most notorious use must be for the suppression of the smell from cannabis plants in illegal growing rooms.”
    http://www.emanator.demon.co.uk/bigclive/ozone.htm

  2. Just quietly, I think the ozone layer and it’s supposed diminishing is a load of old cobblers in the same vein as say AGW. The nuts have been in charge for quite a while now.

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