Recently, I found this interesting video during web surfing on YouTube (link is shown above). A dry-erase marker, a smooth surface and some water make the stickman float magically. Even some people doubt that the video must be edited with some special effects.
So why a dry-erase marker can be so magic?
It started with the special ink of the dry-erase marker. The modern dry-erase marker has four basic ingredients:
The alcohol-based solvents to dissolve other ingredients;
The pigments (colouring);
The resin, which is added to help the ink spread evenly on the board surface and help the ink stay cohesive;
The release agent, taking the form of an oily surfactant or co-solvent such as liquid paraffin or esters, prevents the ink from setting. (Plug: the biggest difference between permanent marker and dry-erase marker it that the permanent marker does not have a release agent.)
The release agent will be dissolved in the solvent with other components to form the ink. When the ink is written on the surface, the solvent is going to evaporate quickly while the oily release agent will take effect to isolate the colouring and resin from the writing surface. That is why we can easily wipe the handwriting off the whiteboard or flush the handwriting away from the smooth surface. But If you observe very closely, you will find the trace of the release agent, though it is colorless.
But how could the stickman keep its shape?
This is because of the resin, which adjusts the ink to be less sticky and forms a thin-film. This thin-film is not soluble in water and has less density than water. When water was dropped onto the flat surface, there is a buoyancy force overwhelming the slight stickiness of the ink so that the stickman floats onto the water surface.
Now, I will high recommend that you should have a try to such a fun experiment~
Dry-erase markers could work well on the smooth desktops or ceramic plates, but if you are too lazy to clean the surface, then aluminum-foil paper would be your wise choice.
Pour water gently, otherwise, the thin-film will be easily broken.