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Scary Soap Science Kit Facts and Cool Details

Here's a weird fact: cooked soap has been around for nearly 5,000 years, and the Babylonians used it to make their hair solid, greasy, and shiny! About 2000 years ago the Gaels, a tribe in Gaul, most of which is now France, made soap from goats' fat and Beachwood ash. Not surprisingly, they stayed dirty and goopy according to Pliny the Historian. It was a long while before we discovered its cleaning properties.

Nowadays soaps are still made by cooking an oil or fat with an alkali (lye or ash). The oils are usually vegetable oils such as palm oil or olive oil. Our clear soap is base made from glycerin and is very kind to soft skin. Our soap kits also include titanium dioxide, which is the whitest and safest pigment in the world. You can find titanium dioxide in sunscreens and toothpastes, too. With our dyes and fragrances, now you can invent the world's most amazing soaps. You're making your own soapy fun in the bath tub!

The Chemistry

Many soaps are mixtures of sodium (soda) or potassium (potash) salts of fatty acids which can be derived from oils or fats by reacting them with an alkali (such as sodium or potassium hydroxide).
The safest soaps are nearly neutral, with a pH of about 7. PH is a measure of acidity or alkalinity. In the safest soaps the alkali has been reacted and some oil still remains.
Some cheaper soaps have traces of alkali and a pH higher than 7. These soaps can irritate your skin. Check your soaps at home with litmus paper or Universal Indicator to find out. Check your skin pH too. Do the pH of your soap and the pH of your skin match?
Soaps work because they have a very odd molecule. One end of the soap molecule loves grease, muck and oil: the lipophilic, or fat-liking, end. The other end loves water and watery mud, stains, and goop: the hydrophilic, or water-liking, end.
So, when you wash with water and soap, one end of the soap molecule combines with oils and the other combines with water. This releases most mucky stuff our skin accumulates.
Our titanium dioxide pigment soap has the whitest safe pigment in the world in it. The oxide is a superfine powder suspended in soap – a suspension. It is not actually reacted with the soap.

The Physics

Soap changes the surface tension of water. Surface tension is the skin water seems to have when in contact with air. Bugs walk on it, feathers float on it. It stops water wetting oily things. Soap reduces that surface tension, sinks floating things, and degreases surfaces -- making them "wettable."
Hot soap takes up more space than cold soap. So when you cool the soap completely it should be easier to separate from the mold. It is also less dense so you can float hot soap over cooler soap!
It also changes state from solid to liquid very rapidly at about 60° C (about 140° F). This is fun to watch. It is melting – not dissolving.
We've noticed the hot clear soap is clearer than the cold clear soap. Its optical properties are different when solid. Do you have an explanation as to why this is true?

A WILD Career
Now, you may be thinking, "What's soap got to do with real science?" Our answer is, simply: everything! Soaps and detergents are used in all aspects of industry, and not just for scrubbing dirty kids or doing the dishes. The pressure is on for soaps and detergents that are sourced entirely from ethical, sustainable, and clean origins. Plus they must do just the job we need and then, basically, "switch off." Soaps and detergents in the environment can kill plants and animals by de-oiling or de-waxing them. They also can have many other adverse effects. Biodegradability is not always a good answer. You must be sure what is left over is harmless or beneficial. Can you be the one who discovers the cleanest way to keep the world clean? Well, until that time comes, have some good, clean fun!

Additional Experiments

Try making gardener's or mechanic's soap by mixing some fine sand into the soap.
Try making herbed soaps with dried herbs and even dried flowers, which can make very interesting perfumed soaps.
Try oatmeal soap, which is cleanses very gently, and perhaps add some chamomile for an added olfactory calming effect.
Some soaps have fine clay in them; clay soaps are supposed to be good for very oily skin.

Please let us know about all of the superb soap that you create!

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