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...or at least I thought so, when I saw that the ink that was on my whiteboard last night became really messed up the next day.

The image below shows my whiteboard before (on the left) and after (on the right). The time span was one night.

The image below shows my whiteboard before (on the left) and after (on the right). The time span was one night.

As you can see, the words became really squiggly, and they mostly travelled downwards.

When I woke up, a few hours before I noticed my whiteboard mess, I noticed lots of condensation water on my whiteboard due to my air-conditioner (my whiteboard is made of glass, if it matters).

My theory is that the water pushed the oil surfactant* of the marker ink mostly downwards. The oil surfactant in the ink coats the board to ensure easy erasing, so the oil should be the closest chemical to the board. Since oil and water are immiscible, the hydrophobic oil ended up being pushed away by the sliding condensed water (sliding due to gravity) and the ink travelled down.

However, my theory does not explain why the ink travelled upwards in some parts of the board. I have not shown it here due to sensitive information.

  1. Is my theory lacking? What do you guys think about this phenomenon? And no, it wasn't a prank.

  2. Can the ink travelling in directions other than downwards be explained?

*Regarding ingredients, all alcohol-based dry-erase marker inks contain 4 basic ingredients:

  1. Release agent- an oily (can be simply a mineral oil) surfactant or co- solvent which will coat the board to provide easy erase barrier (such that the colorant slides off of the board surface and does not penetrate or stain over time)
Melanie Shebel
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rhyaeris
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    A nice thing to do , would be to watch it or record it overnight so you can actually see what is moving where and if you can find some pattern in those movements. If it doesn't happen when you're watching, then probably you should call Sam and Dean. – Quark Feb 06 '16 at 14:08
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    Draw a straight line, spray it with water and see what happens. – Ivan Neretin Feb 06 '16 at 15:55
  • Start adding salt to your dry erase ink. – SendersReagent Feb 06 '16 at 18:21
  • Is an air duct nearby? – Agriculturist Feb 26 '16 at 18:43
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    This is a very unformed idea, so I'm hesitant to write it up as an answer (feel free to run with it if you like it, anyone). What if the movement wasn't due to condensed water sliding around due to gravity, but instead variations in which parts of the board were slightly moistened varying with respect to time. Downward motion would be favored (b/c of gravity) but you could still have patches of moisture develop above your writing that pulled the letters upward. In any case, this is a really cool phenomenon, thanks for sharing and I hope you get your answer. – Jason Patterson Feb 26 '16 at 23:18

2 Answers2

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This is a wild guess, so I am open to criticism.

Brownian motion could explain this phenomena.

  1. Water was on the board, so it is possible a film of water condensed on the board some time in the night. This means the humidity was high while the board was still relatively cool. This film may have allowed the oil particles to suspend.
  2. The ink bound tighter to itself than the non-porous glass board, and the ink itself may be buoyant in water. The ink binding to itself explains why the letters stayed semi-intact instead of diffusing into a mess.
  3. The water molecules are moving constantly which would allow the bigger particles, which in this case would be the letters, to do the random walk characteristic of Brownian motion. (As a note the random walk characteristic of Brownian motion tends in the direction of gravity.)
  4. The diffusion coefficient of the letters would be temperature dependent, so the temperature in the room may have briefly spiked just warm enough for the oil to diffuse some then it came back down so the ink did not run completely off the board.
Agriculturist
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    Brownian motion does not apply to macroscopic objects of the size of the letters. Even a particle with a radius of 0.001 mm would move less than 1 mm under the above conditions. See A. Einstein, Ann. Phys. 322, Nr. 8, 1905, p. 559 (http://www.physik.uni-augsburg.de/annalen/history/einstein-papers/1905_17_549-560.pdf). – aventurin Feb 27 '16 at 21:58
  • I remember Brownian drift entering into certain diffusion calculations, though the timescale was long. You may be right though, it may be much easier to argue some form of covective drift as opposed to a Brownian drift. – Agriculturist Feb 28 '16 at 01:13
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i guess this movement is slightly affected by the motion of the air in your room. or else it is possible that as long as your ink is wet it will slip down ,but as it is very slippery the gravity dosen't affect the ink that much and so the ink travels upward .p.s. it's my wild guess

Noelle styles
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