How Soap Cleans

Soap does an amazing job of cleaning. Plain water cannot remove grease and oil because water and oil do not mix. Soap is the key that connects them. Soap molecules have one end that loves water and one end that loves grease. This special design lets soap grab dirt and wash it away.

The Two-Ended Molecule

A soap molecule has a hydrophilic head that is attracted to water and a hydrophobic tail that is attracted to oil and grease. When you wash your hands, the tails burrow into the grease. The heads stay in the water. The soap surrounds tiny bits of grease in little clusters called micelles.

Washing It Away

Once soap has surrounded the grease in micelles, the water-loving heads pull the micelles into the rinse water. The grease floats away with the water. This is why you need to rinse with water after using soap. Without rinsing, the dirt would just stay on your skin inside the micelles.

Fun Facts

• Hot water helps soap work better because heat makes grease softer and easier to remove.
• Dish soap is designed to be especially good at breaking up food grease.
• Soap works on viruses too, because many viruses have a fatty outer layer that soap destroys.

Did You Know?

Ancient people made soap by mixing animal fat with ash. The ash provided an alkaline substance that reacted with the fat to create soap. This basic recipe has not changed much in thousands of years!