The Spangler Effect - Color Changing Milk Season 01 Episode 18

STEVE SPANGLER: Mmm.
Cookies and milk--
that's a pretty good combination.
There's a lot of science in cookies.
There's a lot of science in this chipotle sauce, probably.
But that we're not talking about.
We're talking about the science of milk today.
And there's some really, really cool, believe it or
not, colorful science of milk.
Watch this.
I'm Steve Spangler, and I'm all about making science fun.
For the last 20 years, I've been teaching ways to turn
ordinary science experiments into unforgetable learning
experiences.
I have an amazing team who will do whatever it takes to
affect the way people think about science.
And to do that, I live by one motto--
make it big, do it right, give it class.

Watch this.

See this amazing burst of color that's here?
In order to understand how milk does this, you have to
understand something about the chemistry of fat, the
chemistry of water, polar, nonpolar, hydrophilic,
hydrophobic--
most importantly, the chemistry of this amazing
substance called soap.
Well, if you take a look at the science of milk, it's
really a combination of fat and water, right?
And all different kinds of fat-- so that's
fat free or 1% 2%.
If we're going to understand how this burst took place,
let's just break this component down and start with
the water component itself.
So in a plate goes just a little bit of water.
And to the water, we add just a couple drops of food
coloring so that we can see the movement--
so a couple drops around the circle.
And now, the last step is just a little bit of soap.
We're just using regular dish soap here.
And I don't need a tremendous amount so I have a little
portion cup.
And our soap is perfect.
Now, in order to dispense it, I'm just using a cotton swab.
So a little bit of the soap on the cotton swab, and now,
watch what happens.
You have to look here in the very middle.
Watch.
Did you see little burst of color that was there?
That's it.
That's our burst.
It's very different from the milk that we had before.
See, the milk had this churning kind of action.
This does actually nothing except for that initial burst,
which means that the soap helped to break up the surface
tension of the water-- that layer of the water that the
molecules hook together.
So the hydrogen bonding allows the water to form almost a
skin, so to speak.
And the soap, of course, breaks that skin and breaks
the surface tension.
But we don't get the bursting.
So it really is not a phenomenon of soap and just
water here and food coloring.
There has to be something with the fat.
See, milk is really a combination of polar and
nonpolar materials.
Polar would be water.
Nonpolar would be the fat.
Now, they say that there's fat, also called lipids.
Maybe The best way to explain what nonpolar would be is to
use this model of these little yellow sticks.
They're called lipids.
See, they're nonpolar in that they're just these long chains
of molecules, so to speak.
See, fat is nothing more than a combination of hydrogen
molecules hooked onto carbon.
And this long chain makes the fat.
See, there's no head and there's no tail.
It's just this long chain.
And this is what we're going to use to represent the fat.
Soap, on the other hand, is a combination
of polar and nonpolar.
And that's why we're using these matches to
represent the soap.
Look at this.
The base of the match here, or the long part, is going to be
used to represent the nonpolar part, very similar to this
part that you see over here with the fat.
But see the very end of the match?
That's the head.
And let's call that the polar part.
Now, water is a polar material.
It's a polar solvent.
So water now dissolves in the head of the match.
And the rest of that match there now wants to attach to
something that it's like.
You've heard the thing "like dissolves like." Well, it
wants to go attach itself to anything
else that is nonpolar.
Look and see how it attaches to the fat.
It's a matter of just matching this up.
The other part, which is the polar part, the head, now
washes away in the polar solvent, which is water.
That's a lot of chemistry to simply say that this is how
you get clean, but this is exactly how they made soap
many, many, many years ago.
They took white wood ash, very alkaline, or
they could take lye.
They would combine that with a little bit of water and then
add and animal fat to that, a little bit of salt, mix the
whole thing together, and it made for this perfect material
that would literally cover your body, remove the grease
and the dirt, and then wash away in the water.
But some of you need an even more scientific explanation of
this hydrophobic, hydrophilic, polar, nonpolar.
And for that, we turn to our friends at Crash Course!, who
know exactly what to say.
HANK GREEN: The fact that water is a polar molecule also
makes it really good at dissolving things, which we
call-- it's a good solvent, then.
Scratch that.
Water isn't a good solvent.
It's an amazing solvent.
There are more substances that can be dissolved in water than
in any other liquid on Earth.
And yes, that includes the strongest acid that we have
ever created.
These substances that dissolve in water--
sugar or salt being ones that we're familiar with-- are
called hydrophilic.
And they are hydrophilic because they are polar.
And their polarity is stronger than the cohesive
forces of the water.
So when you get one of these polar substances in water,
it's strong enough that it breaks all the little cohesive
forces, all those little hydrogen bonds.
And instead of hydrogen bonding to each other, the
water will hydrogen bond around these polar substances.
Table salt is ionic.
And right now, it's being separated into ions as the
poles of our water molecules interact with it.
But what happens when there is a molecule that cannot break
the cohesive forces of water?
It can't penetrate and come into it.
Basically, what happens when that substance can't overcome
the strong cohesive forces of water-- it can't get inside of
the water-- that's when we get what we call a hydrophobic
substance, or something that is fearful of water.
These molecules lack charged poles.
They are nonpolar and are not dissolving in water, because
essentially, they're being pushed out of the water by
water's cohesive forces.
Water--
we may call it the universal solvent, but that does not
mean that it dissolves everything.
STEVE SPANGLER: So you get this hydrophobic, hydrophilic
thing, right?
Fat being hydrophobic, correct, and the hydrophobic
end of the soap, and then the head of the match being
hydrophilic, or water-loving--
that's the part that just simply washes away.
What does all this have to do with bursting milk?
Well, now you start to see the alignment of the molecules
that take place in milk.
Well, we're back to the milk.
I selected milk for this example that has a lot of fat.
It's whole milk--
lots of fat.
Of course, there's water.
So if you can imagine this on a microscopic level, as soon
as I tough it, you now have the hydrophobic end-- that's
the long end of the soap--
now trying to hook on to the hydrophobic end of the milk.
And this moving around these tails--
kind of whipping around-- is exactly what you see as the
milk starts to move.
Watch.
See, it's the hydrophobic end.
It's the hydrophobic end of the soap now hooking onto the
hydrophobic end of the milk.
And you can see the movement that's in there.
Literally, we're seeing molecules in motion as the
milk starts to move around, and of course, realigning
itself so that the hydrophilic, or the
water-loving end is close to that of the
water as it moves around.
And you now get to see this beautiful movement inside just
because the molecules are chasing themselves around and
realigning.
So we're going to turn this into a real science
experiment.
It means we have to compare something.
And why not compare the different kinds of milk?
So look over here-- fat free milk, 1%, 2%, whole milk, half
and half, and finally, buttermilk.
Now, it's really important as you're doing your comparison
to make sure that all of the milk is the same temperature.
So we've let all of this sit out at room temperature so
that we're comparing this.
The real question would be does it change at all if you
heat it up or if you get it colder?
Different question at a different time.
Right now, we're simply observing the differences in
fat for all of the milk.
And finally, every great science experiment has to have
a great hypothesis.
So our hypothesis today has to be which one
will burst the best?
The one with the most fat or the one with the least fat?
Lock it in and watch this.
Let's start with fat free.
Watch.

1%.

Wow, we get a great burst on 1%.

All right, 2%.
Here we go.
Wow, even better.
Here's whole milk.

Beautiful.
Table cream--
lots of fat in table cream.
Watch.

Look at this continued churning.
And finally, who doesn't like a little buttermilk?
You know, it leaves that kind of feeling in your throat.
I know some of you have already tuned out.
Watch.

Nothing.
Well, outside the buttermilk, which was just too viscous to
move around, the one with the most amount of fat is the one
that gives us the best bursting, although, if you
take a look at each one of these, you do see some
movement, but it decreases as you go from whole milk, 2%,
1%, and just very, very little movement at all with
the fat free milk.
What a cool way to understand the science of polar and
nonpolar, hydrophilic, hydrophobic, and the science
of soap using something simple like milk.
Well, it looks like milk, but it's not.
It's Elmer's Glue.
See, Elmer's Glue, chemically speaking,
is polyvinyl acetate.
It's a thermoplastic polymer.
It is unusual because it has a polar part that
dissolves in water.
But it also has a nonpolar component.
And you know what we can do if we have something that has a
polar and nonpolar component.
Get the food coloring.
All right.
This one here-- let's start with a little bit of Elmer's
Glue and even less water.

Now, if I was doing this for science project, I would
measure this out so I could call it a 90% solution of glue
or an 80%, whatever it is.
Here, I just want to test the hypothesis that if we add some
water, that it's going to give us some pretty good bursting
of those colors.
Watch what happens.

There's the movement that we wanted.
Look at this.
It's fantastic.
You almost get this combination of what we saw
with the buttermilk.
Ah, look at the little fingers that are kind
of coming out here.
Yet you get more movement than we saw with just the regular
Elmer's Glue.
Maybe the best part of this is what happens
when you let it dry.
See, normally, you would just dump the milk out.
But if you allow the Elmer's Glue to dry, especially on
these plastic plates, you get something very cool.
Remember, it's not milk.
All of these plates have Elmer's Glue.
The only difference is the amount of water that
we put in each one.
And the best part is, over time, they'll dry.
Well, if there's not too much water, they'll dry.
And watch what happens when they dry.
You can literally just peel them out.
And it looks like this.
Put them under the flashlight and take a look at this.
You get this beautiful kind of stained glass window effect.
Well, you have some fairly simple materials to learn some
high level chemistry.
And if you use the Elmer's Glue solution, you get a
keepsake that's pretty awesome as well.
And best of all, at the end of day, you've got a whole lot of
milk and some cookies left over.
Who doesn't like a little treat?
Oh, god.
That's glue.
Higginsworth!
God, that's horrible.

HIGGINSWORTH: Close the door.
Stop wasting energy.

STEVE SPANGLER: Science of milk.