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Archimedes' "Eureka Bathtub" Russian Mountain

displacement keeps bathtubs on track, makes roller coaster "safe"
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Imagine you arrive at a carnival, and they have an old-school "Russian mountain" style roller coaster made of ice, with sleds sliding down the slopes rather than rails with wheels. However, rather than a gentle slope, this Russian mountain has complex banks, loops, and curves in the track, much like a bobsled course or a modern roller coaster. Therefore it is necessary to keep the sleds at the same weight so that they would not fly off the track.

This is accomplished by a sort of "Archimedes' bathtub" situation with the sleds. Each is filled with warm water to the brim before the passenger gets in, so that no matter the passenger's size, the car would weigh the same, and therefore have predictable physics. Excess water sloshes out and keeps the tracks icy. Before being pushed down the hill, the bathtubs/sleds are fitted with a rubber cap much like that of a kayak, with the passenger's head poking up out of a hole. This is to prevent more water from splashing out and changing their weight during the ride.

An added benefit to the ride would be a nice hot bath for each passenger. There could even be an option for adding soap, so that the sloshing water would scrub them clean. Speaking of sloshing, it might be good to add some sort of baffles so that the water does not move around too much and cause instability.

discontinuuity, Jan 24 2015

Archemedes' bathtub http://en.wikipedia...imedes.27_principle
displacement, eureka, that whole business [discontinuuity, Jan 24 2015]

Russian mountains http://en.wikipedia...i/Russian_Mountains
Precurser to modern roller coasters. Ice-covered slopes with sleds. [discontinuuity, Jan 24 2015]

My friend's photoshop illustration of this idea http://i.imgur.com/KrSICIc.jpg
My friend Pete (on the right) came up with this while high on Nyquil. Please note that it has very little to do with my original idea. [discontinuuity, Jan 26 2015]

Wood-burning hot tub, for bungston http://www.skymall....t-tub/28592GRP.html
the coil is a hollow tube that heats the water with a thermosyphon action [discontinuuity, Jan 27 2015]

Fireplace Cobra Fireplace_20Cobra_20home_20heat_20adaptor
[bungston, Jan 27 2015]

[link]






       After this idea, who wants an ordinary domestic bathtub?
pocmloc, Jan 24 2015
  

       Although I love the title of this idea, I feel I should point out that the method described would displace the passenger's volume, not their weight in water. If you really wanted to use archimedes to equalize the weight, I suppose you could have the person sit in a small boat which then floats in the bathtub.
mitxela, Jan 24 2015
  

       Just fill the tub until weight equalises. (+)   

       The point of archimedes discovery was that (sinking) objects displace their volume, thus allowing him to measure the volume of the complex object (a crown) and calculate it's density. I think the discovery that floating objects displace their weight came later.   

       However, to get the result you want, you could use a denser fluid (highly saltine water would be fine).
MechE, Jan 24 2015
  

       Be that as it may, the disparity between a skinny kid and an overweight adult would be lessened quite a bit.   

       Of course, in the loop-the-loop or a tight curve, centrifugal force would pop the less dense passengers out of the water like a cork.
FlyingToaster, Jan 24 2015
  

       Wouldn't most people float with just their heads above the water? Or am I unusually buoyant? Anyway, the problem with highly saline water is that it would melt the ice. Maybe custard is in order.   

       A loop-the-loop or a banked curve would actually keep the passengers and water stuck more solidly in the bathtubs, if the track is designed properly.
discontinuuity, Jan 25 2015
  

       I would hope the Rubber Duckies are equipped with lanyards for safety sake. I highly approve of this half-baked idea, and award you one bun [+].
Grogster, Jan 25 2015
  

       Okay, I might be exaggerating a little but, if you're lighter than the water, increasing effective gravity will push you out of the water more... no ?
FlyingToaster, Jan 25 2015
  

       No.
pocmloc, Jan 25 2015
  

       Obviously some front for a secret research project into high velocity discarding sabot loofahs...devil to make that much ice out in area 51. The whole thing being headed-up by Superman's arch rival Lex..
not_morrison_rm, Jan 25 2015
  

       //No// then explain centrifuges.
FlyingToaster, Jan 25 2015
  

       // if you're lighter than the water, increasing effective gravity will push you out of the water more... no ?//   

       Yes. And far be it from me to suggest that only a dolt would disagree.
MaxwellBuchanan, Jan 25 2015
  

       I disagree.
not_morrison_rm, Jan 25 2015
  

       //I disagree.//   

       Well, so do I. Simple calculation shows that you're right, and [MaxwellBuchanan] is wildly wrong.   

       If you have a cube of material with a density of 0.5 grams per cubic centimetre, it will float on water with exactly 1/2 of itself submerged - whether at 1G or 1000G.
MaxwellBuchanan, Jan 25 2015
  

       I'm not sure if we're all on the same page regarding centrifugal forces. Since the passenger would be sitting almost totally submerged in the bathtub, there would be no more displacement. If the sum total of acceleration vectors is pointing up relative to the bathtub's frame of reference, all the water would be pushed down into the tub and stay put.   

       Sort of like the old "swing a bucket full of water around on a rope" trick: http://youtu.be/csKOz56ck3g   

       The kayak cap and internal baffles would keep water from sloshing out.
discontinuuity, Jan 25 2015
  

       okay, how about "float with extreme prejudice" then.
FlyingToaster, Jan 25 2015
  

       What a fine idea. The physics. The rollercoastering. The spectacular and impractical danger of the endeavor. I do not understand how this is Russian - maybe there is some roller coaster called Russian Mountain? Or maybe this sort of cavalier imperviousity to possible lawsuit is a Russian trait?   

       And when I read about the rubber caps I envisioned them on the protruding heads of the riders as well as the tubs. Bravo!   

       If some sort of roll cage were affixed maybe this could be sort of safe too? Or if the entire affair was conducted in ice lined tunnels?
bungston, Jan 25 2015
  

       Driving a bathtub, no matter how accurate the 'weight' is, is still the uncontrolled fundamental. Those luge/bobsled guys leave the track occasionally.
wjt, Jan 26 2015
  

       Freeze the water after the rider gets in, that would obviate sloshing.
pocmloc, Jan 26 2015
  

       + Bun from the title alone! I'll go read the idea now!
xandram, Jan 26 2015
  

       //the bathtubs/sleds are fitted with a rubber cap much like that of a kayak, with the passenger's head poking up out of a hole.//
We're all cool with this, yeah? OK, cool.
calum, Jan 26 2015
  

       Very good illustration, I would say it captures the idea rather well.
pocmloc, Jan 27 2015
  

       //roller coaster called Russian Mountain?   

       If you read the wiki, it says that when the idea was imported into the US they were called Russian Mountains, but when they did the cart on tracks version and that idea was imported to the Russia, they called them American Mountains.
not_morrison_rm, Jan 27 2015
  

       In the illustration I am intrigued by the flaming spring outrigger attachment.   

       Please invite Pete to come illustrate other ideas. I hope to see the Pete outrigger on others.
bungston, Jan 27 2015
  

       /If you have a cube of material with a density of 0.5 grams per cubic centimetre, it will float on water with exactly 1/2 of itself submerged - whether at 1G or 1000G./   

       True if density is fixed. If the cube is compressible in any way (for example, a cube of cake), would density not increase and buoyancy decrease under increased gravitational pull?
bungston, Jan 27 2015
  

       //In the illustration I am intrigued by the flaming spring outrigger attachment. //   

       See link above.
discontinuuity, Jan 27 2015
  

       I am delighted to read of that hot tub adaptor. With cold weather I have again been pondering my (linked) Fireplace Cobra, and wondering if cold air would actually enter thru the tail, traverse the glowing coils and be spewed into the room for the warming delight of all.   

       If this hot tub deal works, the cobra should too. The coils can get hotter than the hot tub deal, and in addition to rising, the air will actually expand when heated thus producing the desire spew effect.
bungston, Jan 27 2015
  
      
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