(regal orchestral music)
- Soap.
It's one of those wonderful
things that's super easy,
or soap-er easy, to overlook.
It's kind of like air because
you don't really think about it,
at least, until, you run out.
Now the average household is filled
with all different kinds of soap.
You've got dish soap for the
kitchen, body soap for the tub,
hand soap for the skin, and more.
But what exactly is this stuff,
and where does it come from?
Not the soap tree, that's what I thought.
Soap making is an ancient concept,
and recipes for soap date
as far back as Babylonia, around 2800 BCE,
and civilizations around the world
have been making soap
for thousands of years,
but this wasn't necessarily the stuff
that you'd recognize in the supermarket.
These early soaps were made
by mixing animal and vegetable fats,
along with all sorts of oils and salts.
And while the particulars
may have changed,
the basic technique still depends
on the same soap principles.
See, true soap is
essentially a combination
of an acid and a base.
Now, the acid is fat, in fact.
It's fatty acids plus triglycerides,
and the base is sodium hydroxide.
And when these ingredients are combined,
the saponification reaction occurs.
Fatty acids separate
from the triglycerides
and fuse with hydroxide ions,
forming a salt that we call soap.
When you're washing something,
soap is doing two things.
First, it's decreasing the
surface tension of the water.
Second, it's binding to
dirt, oil, and bacteria.
Soap contains a chain of connected
hydrogen, carbon, and oxygen atoms.
Now let's look at this chain.
One end is lipophilic, meaning
that it's attracted to oils,
and the other end is hydrophilic,
or attracted to water.
So when you're lathering up,
the lipophilic ends of these chains
pick up grease and oils on your skin.
Then when you rinse, the hydrophilic ends
of the molecules follow the water.
This means that you can rinse the soap
and the attached gunk down the drain.
Water alone can't get all this junk off,
because water doesn't mix with oil.
Sure, it can wash dirt off
your skin by sheer force,
but it's surprisingly ineffective
when it comes to removing oily buildup.
There are numerous
different kinds of soaps,
and they aren't all the same.
Soap makers may prefer one type
of fat or oil over another,
and many consumers prefer
the scent, feel, or property
of a particular soap brand.
But across the board, one
of the most popular claims
for modern soap is that
it's antibacterial.
About 75% of liquid soaps
in American grocery stores
show the word on their packaging,
and it seems that companies
are continually adding
antibacterial products to their lineup.
But it might not be as effective
as we'd all like to think.
Those antibacterial
components, often things like
triclosan, or triclocarban,
need time to work.
In order for their
antibacterial properties
to really get a fighting chance,
you'll need to leave this stuff
on a surface for about two minutes.
And, as you might guess,
a lot of people just aren't that patient.
The Centers for Disease
Control and Prevention
also notes that antibacterial
soap is not necessary,
but thoroughly washing your hands
with warm water and regular soap
is one of the most effective
ways to ward off infection.
And not be a gross person.
So what do you think about all
this antibacterial soap hype?
Do you think that we're
using too much of it?
Let us know in the comments below,
and be sure to check us
out at brainstuffshow.com
