Science Focus - the home of BBC Science Focus Magazine
How does soap work? © iStock

How does soap work?

Subscribe to BBC Science Focus Magazine and get 6 issues for just £9.99

The magic of soap scrubs down to its love-hate relationship with water.

Asked by: Richard Somerville, Northamptonshire


The structure of soap molecules enables them to remove dirt with ease. They consist of a hydrocarbon chain, with a sodium or potassium atom at the end. The hydrocarbon end is attracted to oil and repels water, whereas the other end attracts water. When you wash your hands, oily dirt particles are surrounded by soap molecules with their water-loving heads facing outwards. This breaks up the dirt and lets it wash away in the water.


Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.


luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.


Sponsored content