Salt (sodium chloride) is an indispensable and versatile mineral with a vast array of historical, biological, industrial, and practical applications, essential for life and numerous human endeavors.
Mind Map
点击展开
点击探索完整互动思维导图
[Music]
it is the multi-purpose jeel and hide of
the mineral World it can save you and it
can kill you it can also conduct
electricity whiten your whites and ward
off the devil it tastes like no other
Rock and just try cooking a decent meal
without it not going to happen we
literally can't live without it the
ceiling's salt the floor is salt the
walls are salt I'm home stand aside
solar and wind could salt be the amazing
energy source of the future now salt on
[Music]
works geologists call it halight
chemists call it sodium chloride the
rest of us just call it salt it's in
nearly everything from our blood to this
Stone and it has 14,000 known uses some
refer to salt as The Fifth Element as
essential to our world as earth air fire and
and
water but what is salt while there is a
technical chemical definition of salt
what we'll be talking about is the
everpresent compound sodium
chloride the sodium is a metal the
chloride a hallogen and the ratio is
about 40% sodium and 60% chloride they
come together and form an ionic bond
when multiple sodiums and chlorides come together
together
they form a
cube when multiple cubes come together
they form a crystal as we're accustomed
to seeing in nature so what talents does
this little Crystal have salt is
hygroscopic a fancy word that means it
attracts water salt dissolves pretty
easily in water once dissolved it breaks
up into its positively charged sodium
ions and it's negatively charged
that makes it infinitely useful in chemical
chemical
applications salt lowers the freezing
temperature of water making it great for
deicing winter roads but it also rusts
vehicles and bridges in the
process the most obvious use of salt is
in our food where it's both a luxury
because it tastes good and a necessity
because it's an amazing
preservative what sets salt apart from
some other resources is that it's
naturally recyclable
so we're never going to run
out if you think about it the salt on
your eggs or on the sidewalk could be
millions of years old so where does salt come
come [Music]
[Music]
from Salt covers the earth it's
everywhere it's mixed in with all the
ocean water that covers the
planet salt crystals develop from
evaporating Salt Water ocean water uh
from dried ocean beds this looks like a
dried ocean bed doesn't
it many millions of years ago after the
Earth's surface cooled centuries of
rainfall turned puddles into oceans the
Ocean Floors were littered with
sedimentary rock which is full of
sodium meanwhile chloride spewed from
vents still the amount of salt content
in these early oceans was likely pretty
low it took billions of years of water
runoff eroding Rock dissolving the salt
and carrying it into the oceans to
create the saltiness we know
today though it varies by location
seawater is roughly 3.5% salt that
translates to about a/4 pound of salt
per gallon of seawater or a total of
nearly 50 quadrillion tons of salt in
all the Earth's
oceans okay so how do we get all that
seawater harvesting sea salt on a grand
scale requires some serious
patience the other key to this process
location location
location you're located on gr Naga
Island the most suddenly island in the
Bahama chain gr Naga is approximately
500 Mi southeast of Miami Florida
at modern Bahamas limited we have a
unique partnership with
nature aside from having access to a
limitless supply of salty seawater this
location is ideal for other
reasons the requirements are high
incidents of uh solar energy as you can
see we out here in the Sun a steady but
not strong wind low rainfall uh High
evaporation large land area that is
suited for solar salt uh production
30,000 Acres of inaga is devoted to the
solar salt
operation each year hundreds of millions
of gallons of seawater are pumped into
these primary
reservoirs shallow basins where the
water will sit exposed to wind and the sun's
sun's
Rays as the water slowly evaporates the
result is a concentrated brine that's
drawn into secondary reservoirs and
eventually into the final concentration pond
pond [Music]
[Music]
each stage becomes a mini ecosystem
based on the increasing level of
salt in our primary reservoirs millions
of microorganisms flow in with the ocean
water also coming in is millions of fish
egg and other marine animal eggs these
ponds are just teaming with wildlife and
a biodiversity of
Life the secondary reservoirs are too
salty to support most life
with the exception of algae and brine
shrimp and only salt loving AKA
halophilic Red bacteria can survive
after prolonged
evaporation the real magic happens in
crystallization I guess to a point where
the sodium chloride in that solution
cannot be held in solution any longer so
it crystallize into a solid once the
salt layer is about 4 in thick the
Harvesters mechanically scarify or break
up the surface and truck it out to the wash
wash
Plant at the wash Plant the salt is
dumped into a hopper and it is conveyed
on a conveyor belt into spiral
classifiers these are washing tubs where
the sediments from the crystallizers
like dirt or sand is washed out of the
product the 1 million tons of salt
harvested here each year mainly goes
toward Road deicing and water
softening all this salt produced with
little human
intervention in some parts of the world
Salt Lakes or oceans evaporated with
zero help from us resulting in Salt
Flats big exposed beds of salt Utah's
Great Salt Lake is a Salt Flat in the
making as is the Dead Sea in the Middle
East you can find Salt and crusted
seabeds in California's death valley and
at the Bonville salt flats in Utah [Music]
[Music]
here in a Salt Flat in Bolivia salt is
collected right off the surface just as
people have been doing for thousands of
years today salt has many uses but in
the beginning it was all about food and
survival we've known about salt
preservative properties ever since uh
the cavemen and so men have been
locating their settlements near Salt
Works salt has been used since antiquity
as a preservative so before there was
Refrigeration people salted meat and
they salted fish prior to Modern geology
and industrialization if you didn't live
near the ocean procuring salt was an arduous
arduous
proposition this made salt precious
trade routes were set up to holl it from
regions salt was valuable in ancient
Rome because it was used to preserve
rations on Long Journeys
the paycheck of the Roman soldiers was
in salt it was called salario from this
salary we be good if we can convince my
people over here to be paying
salt salt spawn countless superstitions
like warning off bad luck by throwing
spelled salt over your left shoulder
into the eyes of the
devil and Proverbs if you read the
gospel of St Matthew S Matthew Matthew
says quoted
Jesus telling his disciples you are the
salt of the
earth with a double meaning basically
having a life with salt with with
interest and also being the
savior of the people of the humanity
it's impossible to imagine that we could
live without salt and that's why our
watch word is salt the essence of
life evaporating seawater is just one of
the ways we get our salt [Music]
fix a dash here a pinch there the salt
we eat comprises less than 15% of all
the salt produced
worldwide but it's the salt with which
we're most
familiar thanks to that unmistaken able
taste but why do we eat salt at
all it's an essential nutrient an
essential nutrient is defined as one
that our body doesn't make itself so if
we don't take salt in we compromise our
health the body contains about 0.15%
Salt by mass so for a 50 kg human about
110 lb that works out to 75 G of salt or 7
7
tablespoons salt is an electrolyte that
keeps our cells muscles and nervous
system working because when you come
right down to it we run on
electricity electrolytes act as the
electrical conductor that allows our
nerve endings to fire our muscles to
move and our thoughts to form well the
human body is actually a machine it's an
electrical machine and electrical
impulses move into and out of the cells
over the cell membranes and that
transmission is facilitated by the
sodium if that's true salt water act as
a conductor connecting two electrodes
lighting this light
bulb pure water doesn't complete the electrical
electrical
circuit I'm going to add a small amount
of household [Music]
[Music]
salt there goes the stir bar and there
is the light as it goes into solution
the water separates the sodium and the
chloride ions and they allow the
electrons to flow from one side to the
other completing the circuit lighting
our light bulb all our bodily fluids are
salty because salt and water are
inherently attracted to each other but
salt where salt goes water will follow
and so if you have too much salt in your
body that can increase your blood
pressure to regulate your blood pressure
if you get rid of salt you'll also get
rid of water in other words too much
salt in your body in your blood attracts
more water than your arteries and veins
are used
to lose the salt and you lower the
pressure how much salt is too much
depends on your size age and
genetics but Health agencies recommend a
daily intake of no more than 2,400 mg of
sodium or about a teaspoon full with
prepackaged and fast foods flavored with
large doses of salt the average American
day but why what makes salt taste so
well salty salt has that unique flavor
because of the sodium ions it contains
picture a tongue if you zoom in very
closely into the tongue you'll find the
taste buds the taste buds are made up of
individual cells and at the tip of each
of those cells are receptors to each of
the different flavors for salt there's a
particular channel that only allows
sodium through so when you eat salt the
sodium from the salt goes through the
channel causes a change in the cell and
that change is telegraphed to the brain
your brain can then detect oh I've eaten
salt according to the fame tongue map
salt is best detected on the tip of the
tongue or so we thought in practice we
now know that isn't true and that you
can detect salt all over the
tongue salt doesn't just add flavored to
it it even preserves something as
potentially dangerous as uncooked pork
which can be full of harmful pathogens
the recipe for making an Italian cured
ham known as Pudo hasn't changed in
years it still depends on salt and just
two other
ingredients the pork salt and Thyme and
us that's t m e time people that work
here they know the meat they know the
salt and they know the time that it
takes to make a
p we consider them P [Music]
[Music]
J if these are the pruto Jedi then this
is their Master pruto actually is the
past tense of the verb
prugar which in Italian means to dry it out
out
and that's just how salt makes raw pork
safe to eat by dehydrating and killing dangerous
dangerous
bacteria we apply the wet salt on the
skin of the
product just to eliminate some eventual
bacteria can can grow at the skin level
but the important salt is the dry salt
which penetrates the ham once salted the
hams will age for about a a year in
different chambers giving the salt a
chance to work its bacteria killing
magic each chamber simulates the
environmental conditions of a particular
season in
Italy that first stage is if you will a
replica of what is the winter season so
winter being cold being humid at least
of course in the Mediterranean countries
the salt Works its way into the ham as
it draws out moisture and inhibits
bacteria activity uh the pruto is safe
to eat because there is no more active
bacteria anywhere within the ham but
theut being safe isn't good enough but
also has to be something pleasant hence
you have the summer and the fall and
that's really where flavor is further
brought out by the
salt as you Traverse this vegetarian
nightmare a 100,000 legs of salted hams
at various stages of completion hang
triumphantly as a testament to time old tradition
but vegetarians don't despair salt can
also render vegetables virtually [Music]
unspoil this salt loving bacteria AIDS
in the fermentation and pickling process
in the process of going from a cucumber
to a pickle the salt is added to the
fermentation bright it suppresses most microorganisms
