Why do fats, when dropped to a brown paper bag, stains a translucent spot when light was subjected to it?

Question

This is about lipids and its properties. Thanks! :)

This is abou the properties of lipids. I used vegetable oil. Thanks!

Answer 1

I believe it has something to do with the fact that the lipid molecules are able to fill in the gaps (the air spaces) between the fibers in the paper, and then produce a semi-transparent film from the paper, owing to the fact that the lipids themselves have some transparency.

Water can do the same thing to a jar filled with ice. You would not be able to see through the individual cubes of ideas which are interspersed with air pockets, because the light would be refracted at odd angles from each ice cube surface, and would therefore not be able to travel in a straight line through the jar. Adding water would fill those air pockets, and create, in effect, only a single surface on each side of the jar--that of the glass itself.

The reason water will NOT do this as well in paper as the oil will has to do with the way in which the water adheres to the paper. Due to its capillarity, it will travel up every single fiber in the paper and not produce a single, uniform surface.

Well, anyhow, that's just my meager understanding of it. When you figure out the actual mechanisms for how it works, let us know!

Answer 2

Are you asking why a bag of Philly Cheese Steaks makes the bag greasy?
Grease penetrates the paper fibers of the bag. The bag absorbs the grease which makes the shiny stain on the bag.

Answer 3

which fats you used dear ..?