Oil Sitting On Top Of Water

This is a cup of water with oil sitting on the top. This picture displays the property of a substance being hydrophobic. In Biology were learned about the structure of a cell and how the inner membrane on a cell is made by phospholipid bilayer in order to protect the cell. It allows only some molecule to pass through into the cell. The phospholipids have hydrophobic tails which which repel water and the oil has a similar property because it doesn't mix with water,