Cornelia Wyngaarden: There is no truth in merchandizing.
Jess Anderson: Not true. Soap *does* get things clean.
Corry: Despite all the miracles of modern science claimed all the new fangled packages, soap does *not* get things as clean as it used to *and* I've noticed that there are less suds as well. Perhaps there is a connection.
this sounds rather like "things aren't the way they used to be", nostalgia, but I don't think there's any basis for this assertion in the actual chemistry involved in soaps / dirt / detergents. They haven't changed in the last several years.
do you actually mean soap, as opposed to detergent?
when you say "things", are you referring to dirty hands or dirty clothes or something else?
soaps are sodium (sometimes potassium) salts of fatty acids. sodium oleate (made from sodium hydroxide / lye and olive oil) is castile soap. a mixture of sodium palmitate and sodium oleate (usually made from palm oil, which contains palmitic and oleic acid) is palmolive soap. soaps haven't changed much in the 2000+ years since they were first made. These days the unreacted starting materials might have been better refined out of the soap, and more perfumes / other additives may have been added, but the soaps themselves are much as they've always been. really not much change in the last century at least. and dirt hasn't changed much either.
laundry cleaning stuff was originally flakes of soap (eg Ivory Snow), but those are really not very common these days, it's usually detergent that goes into the wash-O-matic.
detergents are sulphonates, usually: Na(SO4)R, where R is usually a long-chain hydrocarbon. (a soap is Na(OCO)R ).
Soaps tend to give scum in hard water, because magnesium and calcium salts of the aforesaid fatty acids are not soluble, but instead give scummy precipitates. When you wash in hard water (with Ca/Mg ions present) the first soap into solution comes out as the Ca/Mg salt (scum) and then once you've gotten rid of the calcium/magnesium "hardness" in the water, further soap can do it's cleaning thing. So you need more soap in hard water than the same cleaning task would need in soft.
Detergents do not give such a scum, because the calcium/magnesium salts of hydrocarbon/sulphonates are soluble. That means that you need less detergent in hard water than you'd need soap to do the same cleaning.
Suds are the result of "excess" soap in the system. The first soap into the water will deal with calcium/magnesium if any is present. after that, soap molecules attack any grease present (most of the dirt present will be greasy), forming "micelles" [weeny droplets of grease, with part of the soap molecule inside them] which are water soluble. If there's any soap left over after grease is formed into micelles, then suds will form.
so people are advised to wash their hands with soap to see bubbles. The bubbles themselves don't do any cleaning, but their presence indicates that there is enough soap present to deal with the dirt in the system.
if it's taking more soap/detergent to get to the bubbles stage, then there's more dirt in the system. Either that, or the "detergent product" has less active ingredient and more filler in it.
Chris
there's always chemistry involved. my students make soaps and
detergents every year, and the saponification lab is one of the
most popular
