Why does oil repel water

They can be forced to cooperate, however, and there are several examples of this that are likely currently sitting in your pantry or refrigerator. Called a polar molecule, the negative poles on each water molecule are attracted to the positive poles on other water molecules, and as a result, they knit tightly together with hydrogen bonds. In fact, oil floats on water because it is less dense, with these super-tight hydrogen bonds between water molecules holding them closer together than the bonds between the fatty-acid molecules that primarily make up oil.

As for oil, it is a non-polar chemical. Since the atoms in the fatty acids in oil share their electrons nicely, they usually have no charge, or at least not enough to make the whole molecule polar. Given their lack of positive or negative charge, they are not attracted to a polar molecule like water.

However, although they seem determined to stay apart, it is possible to mix oil and water in a more or less stable solution, and there are several examples of this in your kitchen.

There is a whole section for Fun on our homepage! Do check it out! Thanks for writing in. Hi Mocomi! Thank you so much for all the info! Can you but other subjects rather then science on this website? I like this website… it really helps me …it makes me understand more why water and oil are immiscible…arigato gusaimas.. Interesting information, but only part of a water molecule is positively charged the part around the oxygen atom.

Since water molecules will not let oil molecules through their links to one another, oil gets pushed away from the center of water.

You will not find a jar of water with oil located in the middle -- water molecules will not separate to allow for this scenario. Water molecules exhibit a higher density than oil molecules, meaning that they weigh more. Because it is lighter, oil rises to the top.

If stirred, oil and water always separate again with oil on top. Based in Nashville, Deborah Walden has been writing professionally since , starting as a sports writer for her college newspaper. Walden holds a Master of Arts in art history from Vanderbilt University. Molecular Activity of Water Vs. Water Polarity Experiments. What Happens to Nonpolar Molecules in Water? How Does Alcohol Dissolve Oil? Characteristics of Hydrogen Bonding.