let me take you back in time for a sec
way back to the beginning of this show
remember that the very first thing we
learned is that animals need the energy
from food in order to live and that's
still true but i have news for you
there's something else that animals and
pretty much everything else need to live
too no not youtube videos of cats
although it's hard to imagine life
without them i'm talking about water
living things need water some living
things need fresh water and some need
salt water but all living things need
some form of water to keep on living i
know you know what water is you've seen
it you've done cannonballs into it
you've filled balloons with it and threw
them at people and you certainly drink
it water is one of the most common
substances on earth it covers more than
two-thirds of the surface of our planet
we actually have enough water on earth
to leave a faucet running for 136
trillion years but let's not do that
because for all the water we have
there's one kind of water that we need
to keep us alive and that's fresh water
so what is fresh water and where do we
get it
well it's probably easier to start with
where it's not most of the water on
earth is in the oceans they're huge and
they're also full of salt so most of the
water on earth is actually salt water by
contrast fresh water is found in lakes
rivers ponds wetlands and streams and it
contains very little salt less than 0.1
percent salt actually and plants and
animals including us humans depend on
fresh water because we can't survive on
salt water the amount of salt in salt
water is much higher than what our
bodies can process in fact drinking too
much salt water could even kill a person
which is just one of the reasons fresh
water is so important so now you know
what fresh water is and that it's super
necessary to our survival but if the
oceans make up most of the water on
earth where can you find fresh water
let's take a look at a map to see if we
can find some of its major sources
people who study geography we call them
geographers use maps all the time
they're interested in earth's physical
features like it's mountains deserts
rivers and oceans this map shows all of
the earth's land in water all of the
blue stuff is water but remember most of
the blue stuff is salt water in fact
about 97 of the water on the planet is
salty so let's do some math with that if
97 of the earth's water is salt water
then only about 3 percent of the
planet's total water supply is fresh
water but about 2 is locked up in frozen
glaciers or underground where we can't
get to it so that means of all the water
that's on earth less than one percent of
it is actually accessible to us on the
surface so we can grow crops and have
drinking and bathing water for our homes
now that you know how little fresh water
there really is on earth's surface it
kind of makes sense that most sources of
fresh water would be too small to spot
on a map this big but if we zoom in we
can get close enough that we can spot a
few see any fresh water sources here in
north america i'll give you a hint
they're pretty
great i'm talking about the great lakes
the great lakes hold a lot of fresh
water about 20 percent of earth
available fresh water is actually in
those five lakes but the great lakes are
really big examples of where fresh water
can be found most fresh water is in much
smaller lakes rivers and streams on
every continent those are the small blue
lines and the inland bodies of water
like these so what does this map tell us
well it tells us that there's a lot of
water on earth but very little of it is
fresh water and since humans and many
other animals need fresh water to
survive they're likely to live in
habitats that are near major sources of
fresh water like a river or a lake maybe
one of the great lakes if they don't
live near a source of fresh water then
people have to adapt their environment
to bring the water to them remember when
we talked about las vegas so freshwater
is the substance that keeps you and me
and catbot and grumpy cat and just about
every other living thing alive and it's
all over the earth in extremely limited
amounts so use it wisely
you