“But who may abide the day of his coming? and who shall stand when he appeareth? for he is like a refiner’s fire, and like fullers’ soap:”
“Why does soap get the dirt off my hands?”, I asked my uncle. “Because,” he explained, “soap is slippery, right? So all the germs slip on the soap, and break their necks.”
I recall teaching the subject years later to a chemistry class. “That is so cool”, opined one teenager. Chemistry teachers are not noted for being cool, so, clearly, something about my explanation must have intrigued this young lady.
We all know that oil and water don’t mix. But both oil and water will mix with similar chemicals, especially by dissolving certain solids. Water molecules are polar – that is, they have negatively charged and positively charged ends. They easily dissolve most ionic compounds, as the positive and negative ions get separated, each being surrounded by polar water molecules. Non-polar covalent solids, like grease, will dissolve in oils, which have long non-polar organic molecular chains.
Soap can function in both these worlds. It is ionic, so the positive ion – usually sodium or potassium – is easily dissolved by water. But the negative ion is left with its negative end, which wants to dissolve in water, but it contains a very long organic chain, which wants to dissolve in oil. Therefore, one end dissolves in water, and the other in the dirt on your hands, which is usually oily or greasy in nature. What’s cool about this? Such a phenomenon could not have developed by chance. It is a feature that shows all the hallmarks of design by God.