Everyday Chemistry: How Soap Works

• After eating a greasy cheeseburger, your hands are coated with grease and oil. If you try to wash them with only water, they remain greasy. However, if you add a little soap, the grease washes away. Why?
• Water molecules are polar, and the molecules that compose grease and oil are nonpolar. As a result, water and grease repel each other.
• One end of a soap molecule is polar, while the other end is nonpolar.
• The polar head of a soap molecule strongly attracts water molecules, while the nonpolar tail strongly attracts grease and oil molecules.
• Soap allows water and grease to mix, removing the grease from your hands and washing it down the drain.