Homemade centrifuge solves pressing questions of our time

Would a lava lamp work properly on Jupiter? Google software engineer Neil Fraser built his own centrifuge in order to find out, using an Android phone app to measure the G forces.

The centrifuge is a genuinely terrifying device. The lights dim when it is switched on. A strong wind is produced as the centrifuge induces a cyclone in the room. The smell of boiling insulation emanates from the overloaded 25 amp cables. If not perfectly adjusted and lubricated, it will shred the teeth off solid brass gears in under a second. Runs were conducted from the relative safety of the next room while peeking through a crack in the door.

Turns out, the lava lamp would, in fact, function on Jupiter ... and the accelerometers in the Nexus One are poorly calibrated. Those problems resolved, we look forward to what Big Questions Mr. Fraser and his centrifuge will tackle next.

[Via Kottke]

Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.

Maggie goes places and talks to people. Find out where she'll be speaking next.

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DarwinSurvivor

Shouldn’t the lavalamp be on it’s side to simulate it being right-side up on Jupiter?
Anonymous

Wouldn’t this have been a tad safer done in the open air….i.e. OUTSIDE! (possibly with some sort of safety barrier?) Dread to think of the state of the decor in case of a “slight” mechanical function, captain.
zirya

You don’t need the phone to measure the g-force. You can calculate it based on the rotational speed and the effective radius. Measure the number of revolutions per minute and convert to radians per second. Square this number and multiply by the effective radius (measured from the axis of rotation to the point of interest in units of meters). Divide by 9.81 and you will have the g-force.
pjcamp

What I see is mostly Coriolis circulation.

Because at the end of the day a centrifuge is not a gravitational field.
Dewi Morgan

“outside” implies that there is some such space available. In a city, there just isn’t.
Anonymous

The best result would be for the lava lamp to get flung out the window into the apartment across the street. I’d love to see Niel ring the bell and ask for its return.
S2

Forget the lava lamp, I want that guy’s Erector Set!
dculberson

Yikes. I think drywall would do just about zilch to stop something flying off that beastie! But I’m glad to have this key scientific mystery solved.
- NeilFraser
  
  Re #2: Yes, anything flying off the end of that arm at 3G will be travelling horizontally at 6.47 meters per second.
  
  I’ll be bringing this centrifuge to Maker Faire next month.
  - dculberson
    
    Excellent. I only wish I would fit in a cradle on the end so I could experience the 3G myself.
    
    I just realized the awful pun of having the Android phone at 3G.
Snig

I’ve thought before that a small kitchen centrifuge would be handy, for things like separating egg whites, getting tiny lemon seeds out of the juice, glass fragments out of a broken wine bottle (ok, never safe, but I thought it anyway.) or pitting a whole bunch of cherries at once.
Not a centrifuge this big though, possibly just an attachment for a food processor.
That and a magnetic stir bar and stirrer built into the range for sauces and risotto.
Terry

Neil -

Are you married? And if so, what’s it like to live in a world where you hear things like: “Sure, Honey. Go ahead and build a centrifuge in the house”?
- Snig
  
  This could be disassembled before she got home. Just need to allow enough time to get the lava lamp juice stains off the wall should there be a projectile event.
  - Kimzajc
    
    Can we get through this without assuming (before asking, if it’s that relevant) that Neil Fraser is….
    
    1. partnered
    2. straight
    3. partnered to one of those science-hating harpies (i.e., all women, amirite?!?!?)?
    - Terry
      
      Read the first 4 words of comment #5.
Hans

I can’t think of a reason differential gravity would cause different behavior in the lava lamp. But under the hypothesis that there is such a cause, we could not ignore the differential accelerations experienced between the top and bottom of the lamp. It is not hugely different (owing to the size of the centrifuge) but not negligible either.

I suggest the only way to settle this is a larger centrifuge. There’s also some issues of disturbance at startup, which it would be nice to settle with a longer run.
ultranaut

Seeing things like this makes me want to work at Google. I want awesome coworkers!
aeon

But how much of the movement in the lava lamp would be due to Coriolis forces rather than convection?
- NeilFraser
  
  Re #9: During initial acceleration one can see a gentle vortex forming at the bottom caused by simple inertia (same reason a raw egg doesn’t spin well). Due to high viscosity, this vortex dies down almost immediately once the centrifuge stops accelerating and the G force flatlines. The Coriolis forces then become visible in that they push blobs heading upward to one side, and blobs heading downward to the other side. Coriolis forces only affect blobs which are already moving vertically.
Dewi Morgan

THIS is a Wonderful Thing!

It’s times like this when I want some kind of voting interface, so we can vote for an article to be added to “best of BoingBoing”.
Anonymous

Cool!
The lava looks different though, don’t you think? More kind of squashy. Quite pretty.
PS: Please remember to disconnect the 120V from your audio connector next time you plug in the headphones. :)
KremlinLaptop

I can’t be the only one who expected to hear a thunderous crash once it was up to speed and then switch to a view of the camera as it departs the room through the window at speed?

Insane but brilliant work, truly.
NeonCat

As a Lava Lamp fan, I’ve often wondered if a centrifuge could be used to “renew” LLs. Over time there tend to be tiny bubbles of clear fluid mixing in with the wax, changing the thermal properties involved and generally messing it up. I wonder if you could get a LL up to operating temp, put it in a centrifuge (not necessarily as fast as this one) and if it would force the clear bubbles out of the wax.
Craig Landrum

Want to do this at home when you are married? Marry a gorgeous geek lady.

Helped daughter gather 5 gallons of cow manure and design an experiment to test the energy potential of methane when burned. Assembled everything on the kitchen counter. Sainted geek wife never blinked. Daughter took home school-wide science fair grand prize.

Wife helped me disassemble the 16 x 16ft Moller pipe organ that we pulled from a church in Chicago and used as the centerpiece in our log house in VA.

Wife has two science degrees, does cave diving for laughs, and stands 6 ft 2 in.

And no, you can’t have her. I found her first :-)
- Terry
  
  Dude, I did marry a gorgeous geek lady. And if I pulled this kind of shit in her house, I’d catch a gorgeous geek lady boot in the ass so fast and so hard I’d be hitting 3G on my way across the room.
  - NeilFraser
    
    Re #18: Terry, technically you’d be pulling 3G while in contact with the boot, but that would drop to 0G on your way across the room. I’m just saying…
    - Terry
      
      “Terry, technically you’d be pulling 3G while in contact with the boot”
      
      All of me, or just my ass?
SamSam

Neil Fraser’s site is fun. I think it’s been linked to from BB several times before — at least, I recognize quite a bit of stuff from it.

@aeon: I don’t think that there would be any Coriolis effect worth mentioning in this set up. The centrifuge acts exactly as if the lava lamp were in an increased gravitational field (gravity being indistinguishable from acceleration, after all).
Anonymous

Might be worthwhile to have a bullseye bubble level viewed through a small mirror to get an estimate of what kinds of transient accelerations your getting — Say from an uneven platform or uneven acceleration
Anonymous

Well the forces caused by differing densities would be trippled at 3gs but the viscosity and surface tension would stay the same. So I could easily imagine that the lamp would operate very differently. Of course spinning through the air would also place the lamp in a breeze and cool the exterior more quickly than when the lamp was static. So there would be a greater temperature differential between the top and bottom of the lamp. It might be worth partially enclosing the lamp to see whether this would make a difference in the behavior. Of course a simple postal scale with a 1 oz weight on it would be a simple way of calibrating it.
Mark Dow

Neil,

Have you tried observing a candle at 3g? I’m curious about the role of bouyancy of hot gasses in driving oxygen flow. I’ve seen the results at 0g, and am wondering how much taller a flame might be at 3g.
hadlock

Neil, what exactly were you trying to prove here? That the liquid densities wouldn’t change under different G loads? In theory a lava lamp would stop functioning normally in zero/microgravity, but I don’t see that hypothesis holding up going in the opposite direction. I’m curious what discussion led to “let’s stick this in a centrifuge and see if it really does continue working” :)
snakedart

Technically, if he wanted to answer the question, “would a lava lamp work on Jupiter?” he’d have built a homebrew trash compactor. And the answer would have been “no”.
- SamSam
  
  Technically, if he wanted to answer the question, “would a lava lamp work on Jupiter?” he’d have built a homebrew trash compactor. And the answer would have been “no”.
  
  Huh? Why? The gravity of Jupiter is only 2.5 that of Earth’s (on the surface), so this is a pretty good model. The gravity wouldn’t be strong enough to crush it.
  - dculberson
    
    But the atmospheric pressure is far, far greater. 10x greater while still airborne: http://www.nasa.gov/worldbook/jupiter_worldbook.html but I don’t know what it’s like at the “surface.” Not sure anyone does, as the only probes we’ve sent in haven’t made it very far.
Anonymous

That’s totally more exciting than a regular lava lamp. I vote we all move to Jupiter!
JohnRomeoAlpha

Shouldn’t the lamp be horizontal rather than vertical? Or are you testing if a Lava lamp would work laying on its side on Jupiter?
- dculberson
  
  The lamp seems to be on a gimbal of sorts, allowing it to tilt with the pull of acceleration. So it’s vertical while still and at an angle somewhere between vertical and horizontal while the centrifuge turns. Since the force of earth’s gravity is not negated, it makes sense that it’s not fully horizontal: that would result in a sideways pull from the lamp’s perspective.
MattF

Don’t know if that’s the method I’d have used to debug the accelerometer calibration. But it seems to work, so… ‘ “chacun Ã son goo,” as Baby LeRoy would say.
arikol

Is it just me, or is that thing insanely scary?

In any case, brilliant and fun! Really shows what can be done at home (to explain to the kiddies…yeah, that’s it;)
InsertFingerHere

I love it when the method is far more interesting than the result.

Jupiter has lava? What? OMG that thing is going to go back in time!!!!