Playa science #2: Dust storms

Playa science #2: Dust storms.
By Ess Dot

Like it, or dread it, the sudden blinding disorientation of a playa storm is unavoidable part of life in Black Rock City. How does this work? Here is your latest uninvited dose of playa geek science.

You may have noticed that in a white out, there is a buzz of sand particles that hit your feet and ankles but only dust aloft. The interaction of these large particles and the finer dust is key to the puzzle. The guy who first wrote at length on Aeolian particle dynamics wasn’t a scientist, but a military man. Brigadier Ralph Bagold spent most of his career travelling in the Sahara. Bagnold was obsessed with the desert, dunes and sand dynamics. From all accounts he was much more interested in desert physics than ambushing lost German troops. In 1941, Bagnold published his observations in the classic “The Physics of Blown Sand and Desert Dunes”. The book has been cited over a 1000 times in the past 70 years, including NASA who used his work for modelling dune dynamics on Mars (It’s even been cited by this here lowly graduate student, who wrote a defence of the work for a term paper, lol)
Bagnold’s sharp insight was that airborne particle dynamics can be approximately divided into three phases. When the wind reaches a critical speed it disturbs a first phase of particles called ‘saltators’. When these guys get airborne, they bounce along disturbing myriads of other particles every time they hit the ground. Most of the newly disturbed particles simply creep along at a low level. These creepers are called ‘reptators’. However, a small fraction of particles become properly airborne to become tiny flying missiles and if the wind is strong enough, they add to the existing fleet of saltators. Some of the saltators get caught up, like in stuff around your camp. The newly sedimented, or ‘landed’ fraction, eventually balances out the the influx of saltators creating a steady-state of critters in the air. All this dramarama of flying saltators result in that satisfying tiny buzz on your ankles. The reptators creep along harmlessly eventually forming playa serpents (but that’s for another post!). Unfortunately, the saltators disturb a third fraction specific to the playa; the very fine mud dust that our bikes and art cars release during daily meanderings. When the saltators kick up this dust, along with the added shear force of ground gusts, these tiny 10-100 micron particles stay airborne for much longer periods of time. They are so fine that the sedimentation time is in tens of minutes, instead of ~0.5-10 seconds for the saltators. White out!
Bagnold went on to investigate very rare desert phenomena, such as the ‘singing sands’ which are a natural sound phenomenon sometimes heard near Barchan dunes. This ‘singing’ has been measured at a rumbling 105 decibels. I’ll bet Bagnold would have liked the rumblings of Black Rock City. Wait for the drop, Brigadier Bagnold, wait for the drop.

Through the sandglass we go…
http://throughthesandglass.typepad.com/through_the_sandglass/2009/01/the-man-who-figured-out-how-deserts-work.html
Note that most deserts have a much higher sand – dust fraction than the playa. This is why the sand serpents never get to any great size and why saltators never really get above knee height. That along with the annual winter flood.

Playa Science #1: Giant Smoke Rings

Playa Science #1: Giant Smoke Rings
by Ess Dot!

Every month or two, if you like, I’ll post a short piece on the physics of some of the amazing phenomena that you get to see on the playa. There is a secret world of magic in the sand serpents, the birth of a dust storm, mathematical mud cracks and heat devils.

First off, recall those giant smoke rings that float up, ethereally and silently, into the sky. They are just a semi-stable toroidal vortex, like a donut of air, with smoke flowing from the inside wall of the donut, over the top to the outside. Think of a tornado and mentally grab the top and the bottom and join them up into a circle. It’s exactly the same physics! The equations the same, all you have to do is match the end boundary conditions.
The remarkable thing about these vortices is their relative stability. If you haven’t already seen it… here is one:
http://www.youtube.com/watch?v=kHpBComsngQ

By the way, farting volcanos puff smoke rings, so do dolphins. Youtube it up and find ’em 🙂

Originally posted at https://www.facebook.com/groups/BurningVan/permalink/10151055828762759/

Playa Calendar

HOW TO BRING YOUR CALENDAR WISHLIST OF THINGS TO DO TO BM:

OPTION 1: A notebook works the BEST, with a page for each day & jotting down things you wanna catch.

OPTION 2: Add all FB events connected to your profilehttps://www.facebook.com/events/list, hit the Gears button & Export to Google Cal… You can toggle whether those appear in the Other Calendars section AND/OR peruse the list and Copy the item to your own calendar.

OPTION 3: If ever there was a reason to use Google Calendar, this is it:
1. Add all of your personal/desired events into your personal Google calendar. Include time, location, FB event link, any notes, reminders of what to bring, etc.
Note: You can even create a separate BM one in your account if you prefer, but really, nothing else is going on at that time, so why bother.
2. From the top viewing option buttons, select Agenda
3. From the More drop down menu, select Print.
4. In the pop up window, select Print Range
5. Tick the “Print descriptions” box
6. Tweak other settings, ie, deselect Print Attendees, Print your response, Black & White, etc
7. Click Save As… to download a .PDF preview before you decide to print.

BONUS ROUND: You may also choose to either add or print separately the BMV Google Calendar, that already has all kinds of goodies in it… including DJ lineups for a few of the ‘big’ stages out there… woot. (and no i haven’t paid attention to what/who i’ve added, i only added things as they came across my screen and if i had time to put them in there, don’t diss me for it)

You’re welcome.

Manicure

Tip for my fellow nail-biters (and for non-nail-biters as well): Get a pre-playa manicure! Putting your fingers in your mouth removes the protective oils and dehydrates them. In the arid playa environment, with dust everywhere, this means your cuticles will get trashed and won’t heal until you’re back in moist climes.

Getting a manicure will keep your cuticles in check, and I find I bite my nails less after I’ve had one…getting a mani the week before playa gives your fingers a fighting chance. Happy fingers mean happy burners!

~ Golden Saxomasaurus

  • Miz Anna: Ditto a pedi- If you get the cracked, dry, icky skin removed from your feet before you go, you’ll be far less likely to develop fissures on your soles!
  • Xray November: my lip balm does double duty out there. I rub a lot of it into my cuticles to stop them from getting too cracked and messed up.

Freak Out

Tip of the Day: You’re going to freak out at some point. Whether it’s a major blowout with someone, tripping balls, losing it in a dust storm, or just plain weeping from exhaustion. And guess what? It’s ok. Just pick yourself up, wipe the snot from your face, apologize if you need to, hydrate and take a nap. Because something always goes sideways at summer camp. Just own your own shit, and remember, things’ll work out somehow.

Miz Anna

Sheet the Dust

Tip Today is…..take an extra fitted sheet when you hop outta bed in the morning to greet the day, cover up your entire bed with the fitted sheet. Presto Fact o a dust free barrier to keep your bed somewhat clean throughout the day.

~Yvonne

Hydrate for Health!

Combining MizAnna and Shenanigans tips today into one Hydration reminder.

Shenanigans
In 20 days you may be rolling through the gate. Hot, dusty, already exhausted, and dry as you’ve ever been. Best start hydrating early.

MizAnna
Here’s a tip for today, twigged by the portapotties at White Trash-
Be kind to your innards, lest they rebel. Make sure you’re drinking enough water to rehydrate after a rough night, and enough fibre to keep things, er, moving. Having to hit the john numerous times because you’ve got a touch of food poisoning is a singularly unpleasant experience; having to sit for protracted lengths because you’re bunged up, even more so. Whatever goes in must come out, might as well make it as comfortable as possible.

Disposable Cameras

DON’T FORGET TO BRING::
Disposable Cameras!!!

When you come back, crashing back into realty, it’s nice to have a few dusty disposable cameras to develop when you’re settling back into society. It’s reliving the event all over again when you’re feeling ‘homesick’. Developed and thought out photos last longer than limitless digital copies that sit on your harddrive. *Buy a few in Oregon where there is no tax.

Only bringing 2 or 3 disposables forces encourages you to reflect on what you’re shooting and to play around with composition n shit…

While looking for something I found an envelope filled with 48 exposures of magical times from 2008 and 2010…

~Helissa Mubert

Pee Funnels!

Tips

Any one of these models below will be great… here are some basic tips for any of them

  • clean by squirting water into it from your mouth (take from water bottle or camelback into mouth first)
  • keep a lidded water jug in your tent/van/rv and pee into there during the night, don’t forget to put the cap back on!
  • MAKE SURE YOU take it with you FIRST TRIP to the porta potty in the morning! If there’s a lineup & you don’t need to go otherwise, freak people out by going into the male trough stall & dumping it there.. ha!
Other online lists/reviews:

squishelle’s top pick: the freshette

  • easy to hold
  • retractable tube makes it compact
  • i really like the hard molded plastic on this one, allows greatest control, easy to hold in place, esp when not so sober / waking up in the middle of the night
  • easy to aim the stream into a jug

$27 @ MEC
http://reviews.mec.ca/9421-en_ca/4005-839/sani-fem-freshette-urinating-aid-reviews/reviews.htm

 

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pStyle

hmmm what i DO like about this one is that it’s open likely making cleaning easier but I like the “security” of sealing the Freshette style against my body.

http://www.thepstyle.com/

pStyle - clearStand up and pee with the pStyle

http://bunnywarez.com/catalog/product_info.php/cPath/25_63/products_id/330

 

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Shewee

Just saw this one for the first time, looks good, esp with all one piece hard plastic. Very similar to Freshette, but no retractable tube.
2nd fave i’d say.

a closeup of the shewee

http://www.shewee.ca/

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whiz

$19.75 CAD MEC

tried one of these, didnt’ like at all, soft silicone, difficult to hold, not as easy to spray water into to clean
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P-MATE

is disposable biodegradable, made of cardboard, discreet and  eco-friendly along with easy to use.  Disposable but can be reused up to 3 times. A great value!