Why does coconut oil solidify into a hexagonal pattern


#1

[Read the post]


#2

Molecular homage to our euosocial overlords, clearly.

For Queen and Colony!


#3

This article from Physics Today seems appropriate.

http://scitation.aip.org/content/aip/magazine/physicstoday/article/67/11/10.1063/PT.3.2584


#4

insert random answer from person who knows nothing on the subject but feels like an expert because google.


#5

Because it’s from the future.


#6

Honeycombs are apparently cylindrical when built, but the drying process shrinks and pulls them into hexagons.
A similar physics? I can’t think of why cylinders would form though, but there are rock formations that solidify into similar hexagons, so I can imagine a similar process.
ETA
The geology of the Giant’s Causeway, says that the formations occur due to the speed of the drying and contraction, so I’d guess that if you cooled the oil at different speeds you’d get a different result.


#7

It probably doesn’t make sense to draw parallels with minerals, because minerals are crystal structures. Wax is not, and that changes everything.

Also, don’t dis Google. Do you know how many timers my son has asked me a homework question, and the answer is, “Google is your friend?”


#8

I would tend to disagree, as per honeycombs and soap bubbles having the same effect. It would seem that there are two different explanations for the honeycomb hexagons though.
And yeah, Google (generally leading onto WikiPedia) is indeed our friend. I’ve learned a ton of useful stuff over the years from people ruminating interesting questions.


#9

Hey man,
This is anecdotal and I am not a scientist, but, I noticed on a highly regarded brand of Coconut Oil that it was “non hexane”. Hexane is a hydrocarbon extracted from crude oil whose molecular structure may cause this effect. Hexane is used as a cheap way to extract the coconut oil from the coconut flesh and may actually linger in the oil. I always buy this non hexane brand and live in the South so my coconut oil is essentially always warming and cooling in my house. I have not witnessed this effect. I would like to know what brand this is and if there is a way to do a side by side warm and cool with a “non-hexane” coconut oil. Now I am curious, so keep us posted.
VV


#10

I’ve eaten coconut oil for over 10 years and had it melt and re solidify, a better question is why have I never seen this happen to my oils?


#11

This was a question for thesis proposal defense in graduate school. If you have a liquid between two plate at different temperatures (heat input greater on bottom), you will set up a circulation pattern due to natural convection. If you look at it from the side[x-z plane] (and if the width is great enough) you will see multiple flow cells forming. When you look at it from the top [x-y plane] you’d think you’d see circular cells, but circles do not tile a plane and from the side view we know that there are no dead zone or regions of no flow. Shape closest to a circle that exactly tiles a plane? hexagons. When the oil cooled and solidified the boundaries between the flow cells remain - hence hexagonal prisims.

See http://www.eoht.info/page/Bénard+cells


#12


#13

Ok, the amount of bad information on here is going to make my head explode. Just ignore the following. It’s for my own emotional safety.

Honeycombs don’t dry. It’s wax. Beeswax. They make it as a hexagon and it’s efficient. Wasps make paper hexagons. Yeah, it dries. But it’s hexagon before it dries.
Basalt lava doesn’t dry either, it cools and solidifies. Crack propagation can cause hexagonal columns.
Yes, wax can crystallize. Oils, like coconut, are not waxes. But they can crystallize too. Same as minerals. Same at pretty much everything given the right conditions.
The hex in hexane is totally coincidental.
While there might be a temperature gradient that could cause convection cells, this would tend to mix the oil. These cells show fractionation during solidification. Very common during solidification of mixtures. The small grain sizes near the glass and the columns point to directional solidification.
http://www.tms.org/pubs/journals/JOM/9710/Schulz/Schulz-9710.html has some of the better pictures.


#14

The bees make round cells and then push them out to meet the one next door resulting in hexagonal cells. The cells around the edge are round.

I am not any kind of scientist, but a curious artist, curious about form and where it comes from. I once did a large collage with the pictures from a dictionary. In order to get the pictures as close to each other as possible I adopted a hexagonal grid. So, somewhere along the way bees figured stacking in alternating rows rather than on top of each other was a more efficient scheme (and yes, I do understand how evolution works and am using an informal way of describing it.)

I also once discovered a technique of mixing metallic powder with lacquer and pouring it in a thick coat on a substrate. It would dry after several days in a hexagonal-ish pattern of what I assume were convection cells. After polishing it was quite a stunning surface. I think this is closer to what is going on with the cocoanut oil. My assumption was that the lacquer had the pattern without the powder, but the powder made it visible. Here is some head exploding speculation; the evaporation of the solvent creates a difference in temperature between the top of the layer and the bottom which results in convection that organizes itself into cells that are polygonal because they need to tile the surface.

Sorry about your head parts all over the place. Good luck with the reassembly.


#15

If you packed a bunch of identical balloons into a kiddy pool until there was no space remaining between them, it seems intuitive that they would deform into hexagons except near the edges. If they are all of the same size, skin strength and internal pressure, that is.

If a substance began to gel at equally spaced locii and each locus expanded outwards to the limit available, would not the same thing happen?


#16

Agree – IMO it’s a convection/fluid dynamics/heat flow/etc. mechanism. I bet the conditions have to be just right.


#17

Yeah, now I want to know why does coconut oil not solidify into cool Giant’s Causeway patterns like the one in the picture.


#18

That is a cool place, i hope to go back someday.

I’m wondering if this coconut oil had an adulterant that caused this, or if it was just subject to some strange cooling/heating pattern that triggered an atypical solidification.


#19

Ive seen coconut oil all my life - and it has always liquified & solidified. Never have I seen this. Must be some additive or type of extraction particular to the brand.
Definitely not normal.


#20

hexane is used in the extraction of cheap coconut oil, that would be my first guess.