[ music ]
>> Hello, my name
is Nicole Mann,
and I'm an astronaut
living and working aboard
the International Space Station.
Did you know that our bodies
are made up of 60-75% water
in weight
and water covers roughly
71% of Earth's surface?
Have you ever wondered
what it is about water
that makes it so important
for life?
Well, for today's episode,
we're going to dive into
the unique properties of water
and discuss why water
really is the stuff of life.
Are you ready?
Let's get started.
You know, water
is referred to as H2O.
Two hydrogen atoms
and one oxygen.
It's what we call
a polar molecule.
Polar bonds happen
when there's a difference
in electronegativity
between the atoms
involved in the bond.
In this case, the oxygen atom
is very electronegative,
whereas the two hydrogen atoms,
having fewer electrons
in the relationship,
take on a positive charge.
This structure explains
why water has
very unique properties.
Pure water at room temperature
is odorless, tasteless,
and somewhat colorless.
It is the only substance
that exists as a solid, liquid,
and gas under ordinary
conditions back on Earth.
Unlike most materials,
the solid form of water,
ice, is less dense
than its liquid form.
On Earth's surface,
in the presence of Earth's
full gravitational pull,
ice floats on water.
Because of its molecular shape,
water is often referred to
as a universal solvent,
meaning its able to dissolve
more substances
than any other liquid.
Our bodies need water in order
to carry out many functions
essential to life.
Our kidneys, for example, filter
minerals and waste materials
from our body.
Water, being such
a great solvent,
is able to dissolve
many of these substances
and assist the kidneys
to flush them out.
Up here in microgravity,
we don't have salt
and pepper shakers
like you do back on Earth.
Because of the weightless
environment, using salt
and pepper shakers
is infeasible.
Particles of salt and pepper
would not adhere
to food in microgravity,
and instead, would float away,
clogging the air vents,
contaminating our equipment,
and getting in our eyes
and nose.
Instead, we utilize
water's solvent property
to create a liquid form of salt.
Salt is easily dissolved
in water, and pepper
is suspended in oil
to make liquid forms
of salt and pepper
that we can use to elevate
the flavor of our food.
I'm going to demonstrate
water's properties of adhesion
and cohesion using a washcloth
soaked in water.
What do you think will happen
when I attempt to wring out
the water in this washcloth
up here in microgravity?
Let's find out.
This is just ordinary water
that's going onto a washcloth,
and now you can see
the washcloth is soaked
full of water.
Notice how in space, the water
doesn't leave the towel
when I attempt to wring it out.
Instead, our microgravity
environment, combined
with water's properties
of adhesion and cohesion,
come into play.
So, cohesion is the property
of water where the molecules
are attracted to each other.
Thus, sticking together.
Now, the water molecules
are also attracted to the towel
and to my hand.
This is called adhesion,
and this is because
of the electrostatic bonds
formed between the water
molecule and other surfaces.
A water molecule, having both
positive and negative poles,
means that it can
attract or stick to
many different materials,
no matter their charge.
A plant is able to move water
and its dissolved nutrients
from the roots
up to the rest of the plant
via capillary action,
which utilizes water properties
of adhesion and cohesion.
Each water molecule is attracted
to the other water molecule
and to the tissue
within the plant.
This is the VEG-05 Experiment,
currently being
conducted onboard
the International Space Station.
Today, we are growing
dwarf tomatoes.
They live in this special
habitat which controls
their lighting
and their living conditions.
Astronauts use these tubes
to inject water into a pillow
at the base of the plant.
This provides water
for the plant to live and grow.
Think about all the different
things in your house
that contain water,
from laundry detergent
to ice in your drink,
and even the waters
in the fruits and veggies
that you may be eating
for dinner tonight.
Water is a necessary
part of our lives,
whether you're residing
on Earth's surface,
or orbiting 250 miles above.
Thanks for exploring
the properties of water
with me today.
See you again soon!