How does soap work?

Thursday 12th July 2012
Submitted by Luis Villazon
Richard Somerville, Northamptonshire

How soap cleans

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.

What causes left-handedness?
previous qanda Article
Do you burn more calories during deep thought?
next qanda Article
Q&A Tabs

A lunar month is slightly shorter than a calendar month, so every two to three years, there is an extra lunar cycle above the usual 12. This additional moon is called the ‘blue moon’...

Your DNA is arranged into chromosomes, which are grouped into 23 pairs. When a sperm cell is manufactured, the father’s genome is split in two, so that each sperm receives one chromosome...

Hibernation is a response to cold weather and reduced food availability. Most animals that hibernate are quite small and, as the weather gets colder, they reach the point where they simply can...

Cramp is an involuntary and sustained muscle contraction. It can be caused by electrolyte imbalance, certain neuromuscular disorders or by drug use. But it mostly happens when we're resting. One...

Tropical rainforests don’t experience the winter and summer extremes seen in temperate rainforests. Often, tropical trees grow in a similar way all year round, meaning growth rings are not...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...

We use cookies to improve your experience of our website. Cookies perform functions like recognising you each time you visit and delivering advertising messages that are relevant to you. Read more here