The Pacific Ocean is the
largest body of water on the planet.
It's so big, in fact,
that if you pick this point off the coast of Chile,
and then go directily opposite,
you end up still inside the Pacific Ocean.
It's HUGE.
From this angle,
it really does look like our planet is nothing but water.
Just the ocean.
But the ocean isn't only water.
It's a solution
made out of water, minerals, and salts.
In this video we're going to explore
what dissolves in water, and why
with 6 hands-on activities.
salt crystals,
halocline eggs,
eggshell geodes,
borax snowflakes,
rock candy,
and bath bombs.
Most of the salt in the ocean is sodium chloride.
A compound made of 1 sodium, and 1 chlorine atom.
"I have one too many electrons!"
"I just need one more electron!"
"Do you want this?"
"Yes!"
[ boom ]
"Now we're ions!"
Positive and negative charges attract each other.
And so the sodium and chlorine form an ionic bond.
Water also has a slight positive and negative charge.
You might remember this
from the previous science mom videos.
This is called polarity.
Because water is polar,
it's very attracted
to the ions in the salt.
So when a salt particle goes into water,
the ionic bond between sodium and chlorine is broken,
and the water molecules surround the ions.
This is how salt dissolves.
But how much salt can water hold?
How much salt do you think there is in, say,
one cup of sea water?
This water is from the Pacific Ocean, and it's very salty.
Bleach!
Yeah, can't drink it!
If you drink it, you actually get more dehydrated
and thirstier
because the salt content is so high.
But just how much salt is inside this cup?
Well, if we leave it out for several weeks
and let it evaporate,
we'll find out.
Pause the video.
Make a quick prediction.
It's been a couple weeks now.
The water evaporated, but the salt stayed behind.
And if I scrape this down
so we can see exactly how much is in here,
there's really just a spoonful of salt
inside that cup of water to make it salty.
You can make your own salt solution at home
by adding three tablespoons of salt
to one cup of boiling water.
Three tablespoons is close to being saturated.
That's about the most salt
you can get to go into solution and dissolve.
This is a more concentrated solution
than salt water from the ocean.
And it will begin growing crystals within a day or two.
The crystals will always have a squarish shape to them
because the sodium chloride molecules
arrange themselves into a very organized pattern,
and that pattern is reflected in the larger crystals.
By changing how quickly the water cools and evaporates, you can also change how the crystals grow
making them larger or smaller.
The Great Salt Lake has more than
twice as much salt as the ocean,
which makes it very easy to float.
The salinity is so high,
that I can easily lift my feet, hands, and head
out of the water.
But if I try to do this in a swimming pool?
It's impossible!
I can keep my face and feet above the water,
or my hands and my face,
but not all of them.
Every time I try it, I sink.
Keeping hands, feet, and head out of the water
feels like an impossible challenge.
But in the Great Salt Lake?
It's easy as can be.
The reason my swimming experiences
were so different,
is because the density of salt water
and fresh water
are very different.
In fact, the density of salt water and fresh water
are so different,
that we can layer fresh water on top of salt water,
and they won't mix!
This is called a halocline,
or a salt slope.
The set up for this is a little bit tricky
because you can't have the water mix too much.
So if you take a spoon,
put the spoon right next to the edge there,
and then poor slowly onto the spoon,
that usually works.
If I place and egg in freshwater, it should sink.
It's more dense than the water.
But the salt changes the density of water.
An egg in salt water floats.
And this egg
should hover right around the middle
because it's floating on a layer of salt water,
which is layered underneath a layer of freshwater.
And now, a half hour later you can see that
the eggs are still in their positions
with the one in fresh water being at the bottom,
the one with the halocline layer of salt water
and fresh water being in the middle,
and the salt water one being on top.
Which is pretty cool!
This layer is impressively stable
and in the ocean, there are actually some underwater
super salty lakes that
maintain that barrier all the time.
You can grow beautiful eggshell geodes
by dissolving alum crystals in boiling water.
Please note,
aluminum sulfate and potasium aluminum sulfate
are both called alum.
The potasium aluminum sulfate
will grow beautiful crystals.
Aluminum sulfate,
on the other hand,
will not.
So you want to make sure
that you have the right ingredient.
If your alum has granules that resemble salt
and look like very tiny blocks,
then you're good.
If it's powdery and looks more like flour,
then this is not the alum you're looking for.
It will not give you any crystals.
Make your solution,
and then add food dye and place it carefully
into two heat proof jars or cups.
Then add your eggshells.
Depending on the temperature of the water
and the texture of the shell,
you can get very different looking results.
This one is a surprise.
Look at that.
We got some nice crystal formation
around almost the entire outside,
um,
and some on the inside too.
So,
They're real fun to take out of the jar
because you quite know what you're gonna see
until you take it out.
And don't through out the crystals
that form on the bottom of the jar.
Those can be scraped out
and then boiled and reused
to grow new eggshell geodes.
The reason we're able to get such good crystal growth
with this investigation and the next one,
is because hot water can hold more solute
than cold water.
"Look at us!"
"We can hold so much stuff!"
When the water cools down, the molecules slow down,
and they aren't able to hold as much.
"Uh, I can't hold onto the solute."
"Me neither."
And when the alum falls out of solution,
or precipitates,
it forms into an organized structure,
just like the salt did in our fist activity.
You can grow crystals with borax too.
Dissolve 1 cup of borax into 4 cups of water
and suspend a piece of pipe cleaner
in the solution.
These are also very fast crystals
and will be ready within 12 to 24 hours.
[ music ]
If you want to keep your crystal creation,
then paint it with clear nail polish after it dries.
Otherwise, any water that comes into contact with it
will cause the crystal to begin to dissolve
So far,
everything that we've been dissolving
has had either a metal or a metaloid inside it.
The salt had sodium,
the borax had sodium and boron,
and the alum had potasium and aluminum.
But now, we're going to go to sugar,
which is made entirely of non-metals.
Sugar has carbon, oxygen, and hydrogen,
and that's it!
Just those three things.
And when we dissolve sugar in water
we're not going to get a chemical reaction.
There's going to be no changing
of the bonds in the sugar.
The chemical bonds are going to stay the same.
But the water molecules are going to surround the sugar,
supporting it in solution,
because sugar has hydroxyl groups,
several areas wherethat oxygen is quite electronegative,
just like in water.
"You remind me of me, so I like you!"
And so sugar and water get along really well together,
it goes into solution beautifully.
With each activity so far,
we wanted to make a saturated solution,
fitting as much into the water as we could.
And here's how much salt, alum, and borax
we were able to fit into one cup of water:
3 tablespoons,
a half cup,
and a quarter cup.
So what's your guess with sugar?
How much sugar do you think we can fit
into one cup of water?
Pause the video, make a quick prediction.
The answer is
four cups.
If you don't believe me,
just watch.
[ music ]
A sugar solution this concentrated
will crystalize very quickly
So if you want to make rock candy,
I recommend a slightly less concentrated solution.
For recipies and more information about rock candy,
check out the link to my website below.
Bath bombs are wonderful.
They small great,
they're super fun to watch dissolve,
and they're a wonderful example of how important
water is for facilitating chemical reactions.
"We can't react without you!"
This is citric acid,
and this is baking soda.
If I mix them together dry, nothing happens.
Neither of them react.
If I put them [each] in water, not much happens.
They just dissolve into the water very nicely and quietly.
But now that they are hydrated,
something exciting happens when I mix them:
bubbles!
The baking soda and citric acid react,
producing carbon dioxide gas.
To make bath bombs
you want to mix your dry ingredients,
and then your wet ingredients.
Then slowly and carefully
mix your wet ingredients into your dry ingredients.
If you don't hydrate the cornstarch and the baking soda a little bit,
then they wouldn't hold together to make the bath bomb.
But if you add too much water too quickly,
You'll cause the citric acid and the baking soda to react.
So go slowly,
by the time you're done, the mixture should look almost sandy.
Now, pack them into the mold.
You can put little foam capsules in
as a surprise if you want,
and then let them sit for at least 24 hours to get firm.
Now the bath bomb is ready.
We can put it in water
and enjoy watching a gentle chemical reaction.
[ music ]
I was worried about this video getting too long,
and so I know I went through those six activities
really quickly.
But if you click on the link in the description,
at my blog I have very detailed instructions
for each of the activities,
and as always,
on my website you can also download
a piece of paper
that folds into a little miniature pocket-sized book,
and it has instructions for all of the activities
that we just did,
and some little tips and tricks for having
the science experiments work out right.
So,
our book recommendation for this video is
Rosie Rever's big project book for bold engineers,
by Andrea Beaty and David Roberts.
If you have not seen Andrea Beaty's books yet,
you have got to check them out.
They are all fantastic.
I love them all, but this one is my very favorite.
That's it!
Work hard, grow smart, and I'll see you next time.
Alright, let's try our rock candy and see what it tastes like.
SWEET!!!
Yeah, it's really sweet.
You want me to eat it?
Yes! Eat mine, eat mine, eat mine.
(Sarcastic voice offscreen) "Well that was successful."
This video was made possible by the support of my wonderful patrons on Patreon.
If you'd like to join us, visit patreon.com/JennyBallif.
It's been 2 weeks!
And the egg is STILL on the halocline!
Amazing!
I think the halocline's gonna last longer than the eggs.
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