Source: I couldn't really think of a good title picture for this post. I didn't want to take a picture of the condensation, because that's gross. You could view this one two ways: the bucket is either supposed to be a desiccant full of the water it sucked up, or it's nature dumping water all over the truck.

Continuing my new trend of discussing Californian curiosities,* let's talk about water. Speaking with only the slightest bit of hyperbole, it doesn't rain in the Bay Area from May through September, but it gets decently damp from October onward. And I'm not just talking about rain; some mornings bring with them a thick layer of condensation, which I've addressed before, a long, long time ago.

Back then, I thought the condensation was, in large part, just me breathing in the boxa lot, which seems kinda silly (and gross) in retrospect. I've since learned exhalation only accounts for a small amount of it: less than a cup per night. The majority just condenses out of the air. Normal folks call this 'humidity', but apparently the word escaped me when I wrote that last post.

One thing that continues to perplex me though is how physics decides which surfaces get covered in condensation. The Wikipedia article on Dew, which is riveting stuff, explains it as:

[Dew] forms most easily on surfaces that are not warmed by conducted heat from deep ground, such as grass, leaves, railings, car roofs, and bridges

…which seems pretty straightforward, but my experience has still been kinda confusing. Here's a brief, informal survey of the various damp and dry surfaces of my truck.

Occasionally Damp Things

  • Soft fuzzy blanket
  • Metal ceiling
  • Glass sunroof

Generally Dry Things

  • Other blanket/comforter
  • Metal storage cabinet
  • EPS foam insulation

I vaguely understand it has to do with heat conduction, but, for example, I'd expect the storage cabinet and the roof to conduct heat similarly, both being metal. And yet, on especially moist mornings, the cabinet will be bone dry even when there are literal droplets condensing and falling from the ceiling.

Writing that out, it sounds kinda bad, things being damp and drippy and all. You'd think everything would get moldy and gross and generally problematic, but in the nearly five years I've been doing this, it's been totally fine (well, now that the leaks are fixed). I think that's in large part due to the ventilation provided by the sunroof, me occasionally toweling down the offending surfaces, and, of course, my liberal use of desiccants.

I've faithfully made the trek to Home Depot every October like a weird, damp pilgrimage, purchasing that mystical cat litter in an increasing variety of form factors. I've got the standard tub under the bed, hanging ones for my clothes rack, and little boxy ones for inside my storage cabinet. The desiccants are definitely doing something, because after a rainy season, they're all full of water that they've pulled out of the truck.

The Splash

One other weird winter weather phenomenon I've encountered is, for reasons I might never truly understand, a deluge of water will just pour through the sunroof. It has happened four or five times, and only ever in the middle of the night. I'll be sleeping, and then I'll hear a sound akin to a lot of water hitting the floor, loud enough to wake me up. I get up and sure enough, there's a lot of water on the floor, probably a few cups worth. I usually towel it off, barely conscious and acting purely mechanically, then hop back into bed.

Because of the ungodly hour this happens, my memories are hazy and incomplete. The sunroof is always open, but I don't think it's ever raining, because I try not to open it on nights there's a chance of rain. Plus, rain in the truck is loud and memorable. My best guess is that the open sunroof is good at collecting moisture, which then drops onto the fine mesh I use to keep out leaves and bugs. Once there's a critical mass of water, surface tension (or something?) breaks and the puddle quickly filters through the net and to the ground.

It's either that, or someone is standing on the roof and pouring water into the truck to mess with me. It's more likely than you might think.

*To say nothing of my other trend: writing posts about wildly mundane things.

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