Translucent Spot: Why and Is it Related to Adsorption?

[Harmony]

Why is translucent spot produced when food containing lipid is rubbed against a paper? Is it related to adsorption?

 

[andrevdh]

It means that the light rays are scattered by the fat molecules and can be absorbed and re-emitted internally thereby transmitting some light to the other side. But I do not know how the mechanism actually works.

 

[sir-pinski]

Translucent spot is a common occurrence when food containing lipids, such as oils and fats, is rubbed against paper. This is due to the fact that lipids have a unique property of being both hydrophobic (water-repelling) and lipophilic (fat-loving). When the food is rubbed against the paper, the lipids from the food transfer onto the paper, creating a translucent spot.

This phenomenon is related to adsorption, which is the process of molecules adhering to a surface. In this case, the lipids are being adsorbed onto the paper. This is because paper is made up of cellulose fibers, which have a high affinity for lipids. As the lipids come into contact with the paper, they are attracted to and adhere to the cellulose fibers, creating the translucent spot.

The reason why the spot appears translucent is because the lipids are spread out in a thin layer on the surface of the paper, allowing light to pass through. This is similar to how a thin layer of oil on water appears translucent.

In conclusion, the translucent spot produced when food containing lipids is rubbed against paper is a result of the lipids being adsorbed onto the cellulose fibers of the paper. This phenomenon is related to adsorption and is a unique property of lipids that allows them to transfer onto surfaces when rubbed.