Morgan
International Hazard
Posts: 1694
Registered: 28-12-2010
Member Is Offline
Mood: No Mood
|
|
Leidenfrost effect with hydrogel
The hydrogel in the pan
https://www.youtube.com/watch?v=OfcCsP-T1pc
This was one of the translated comments.
td256 1 week ago
tobi pizda author) Hydrogels are usually presented as a pH-neutral, non-toxic, organic compounds (polymerized form). The fact is that after five
years of virtually the entire hydrogel depolymerized due to natural decomposition processes ... When the hydrogel breaks down, it releases potassium
acrylate and acrylamide. Acrylamide is lethal neurotoxin and has been found to cause cancer in laboratory animals. It easily passes through the skin
and can be inhaled as dust ... Who is at risk of exposure to acrylamide? Workers kindergartens and gardeners, who typically use hydrogels and may be
exposed to them when they are destroyed and become toxic. Homeowners who added the hydrogel-containing mixture, or portions thereof on compost heaps.
Dogs, cats, and
|
|
|
Atrum
Hazard to Self
Posts: 73
Registered: 7-12-2014
Member Is Offline
Mood: Tired AF
|
|
This would make a neat analogy for demonstrating motion of atoms when they are heated.
"Experience is my one true mistress and I will cite her in all cases. Only through experimentation can we all truly know anything." ~Leonardo da Vinci
My inventory
Recently acquired elements: Iodine , Cobalt, Tungsten, Silicon |
|
|
Morgan
International Hazard
Posts: 1694
Registered: 28-12-2010
Member Is Offline
Mood: No Mood
|
|
If there was a way to make a jellied alcohol marble it would be fun to light them on fire as they jumped up and down and there could be flame
colorants too of course.
|
|
|
UC235
National Hazard
Posts: 565
Registered: 28-12-2014
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by Morgan  | | If there was a way to make a jellied alcohol marble it would be fun to light them on fire as they jumped up and down and there could be flame
colorants too of course. |
Since the Leidenfrost effect relies on formation of gas between the object in question (hydrogel, ice, dry ice, etc.) and a vastly hotter surface,
igniting the object and therefore heating the entire thing uniformly would destroy the effect.
|
|
|
Morgan
International Hazard
Posts: 1694
Registered: 28-12-2010
Member Is Offline
Mood: No Mood
|
|
If a hypothetical springy burning gelled sphere would hold together under heat well enough and not "de-gel", it seems like any contact with a hot
surface under the weight of the sphere would cause an ablative effect as the object is in effect pressed against a piece of hot metal which would
cause a sudden evaporation or heat transfer from the solid hot surface, in the vague way a hamburger sizzles more when pressed with a spatula, even if
the hamburger is on fire.
I guess the proof would be in the pudding or rather to do several actual experiments. Perhaps some prototype small, gelled alcohol pellets could be
lit on fire and dropped into a hot pan for an initial crude test. If something ideal with a bouncy coherent quality did work, the fire and sound would
be enhanced, greater than a stationary sphere as the air flow and sudden burst of ablative flammable gases would be fanned by the motion of the
fireball spheres and sudden evaporative impulses. If you've ever tried to blow out an accidental alcohol fire on your hand by waving it rapidly, you
sort of know how the erratic motion excites the flame in an entertaining way.
In summary, it may be possible to flash boil the cooler mass under the tenuous flame of the gelled sphere with an idealized orb of proper
weight/pressure/surface area and bouncy consistancy. As to the effect of heat from the sphere being on fire dampening or weakening/shortening the
Leidenfrost effect is a fair issue of concern. When you think of something like Sterno burning, how hot does the interior get as the exterior burns
away and would that be enough to critically dampen a Leidenfrost effect if a small sphere were pressed against a hot surface? Does water heated to 99
C Leidenfrost any better or worse than room temperature water? With ordinary room temperature water there is a Goldilocks region where too hot or too
cool of a hot surface and droplet size too probably, that there is no sustained resonate feedback effect. And there is some decrease in surface
tension as water is heated up so that you are balancing that factor as well. With thickening, the insulating or heat conducting properties of the
gelling agent might come into play, along with the weight or deformation of the sphere vs the working surface area, the boiling point of the
particular alcohol, the burning temperature of the fuel, and a host of other things that might not come to mind or be revealed until testing. It may
or may not be an easy thing, but it seems like there could be a fair chance of something working with some amount of effort and calibration.
[Edited on 3-12-2015 by Morgan]
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
