there are waiting for the next big snowstorm.

But before the flakes fall, armies of trucks

are loaded full of one of the most important

road safety tools out there – salt.

Along with keeping our french fries on point,

salt, like sodium chloride,

has actually saved a lot of lives,

and probably even more fenders thanks

to its incredible deicing abilities.

(REACTIONS SPLASH)

So here’s a truck throwing salt

all over a wintery road.

Like everything else in the picture,

you can bet that that salt is pretty cold.

This begs the question – how be that

something that isn’t hot is melting the ice?

Turns out, salt isn’t actually about melting.

It’s all about freezing.

The freezing point of pure water rests at

32 degrees Fahrenheit, or 0 degrees Celsius.

When the temperature of water reaches

the freezing point, its normally

free-flowing molecules get trapped

into an organized crystal structures.

This is how ice is formed.

Salt disrupts this process.

Upon hitting water,

salt breaks up into two ions:

one sodium and one chloride.

These two ions then move around

and take up space in between

water molecules, pushing them apart

and frustrating their potential

links to form ice. This disruption

is called freezing point depression.

So to put it simply, salt lowers

the freezing point of water.

But there’s a limit.

Salt can only act as a stable

deicer in temperatures above

16 degrees Fahrenheit (-9 C).

And there’s another drawback to salt.

Considering that over 20 million tons of

road salt is used annually in the U.S.,

all that salt has to go somewhere in the spring.

Of those two ions split from dissolved salt,

the chloride ions can have a potentially

negative effect on the environment.

Chloride can kill small aquatic critters,

dehydrate and kill plants,

alter the composition of ground soil

near roads, and can limit water

circulation that keeps lakes healthy.

All that salt is also corrosive to metal,

wreaking havoc on infrastructure.

And oh yeah, your wheels too.

For these reasons, Sand is used as

an abrasive for an alternative.

Sand is often used because it’s

cheap and maybe cuz folks want

to avoid the chloride issues.

The thing is, salts have a

chemical advantage: because you get

2 or more ions when they dissolve,

you get way more melting power

for the same handful of deicer.

So sand might be cheap, but you have

to use way more of the stuff, and

that can leave quite the mess.

Now for super cold temperatures,

sodium chloride in sand won’t do the job.

Some alternatives that melt ice better

include Magnesium Chloride, Calcium Chloride,

Potassium Chloride, and Potassium acetate.

Potassium acetate is particularly incredible

at deicing because it works at temperatures

as low as -75 degree Celsius, while the rest

of the bunch work around the -20 degree mark.

Although these alternative chemicals

are better at deicing at lower

temperatures, most of them have that

environment damaging Chloride too,

not to mention that they cost

way more than that table salt.

And if you’re buying 20 million

tons a year of the stuff… well,

that’s a lot of money!

So people, keep your eyes on the road, and

thank salt for the fine driving conditions.

Or, on the other hand, you can shake

your fist at it, if you didn’t get

that snow day you know you DESERVE.

Make sure to check out this video

on how artificial snow is made,

and because we’re talking about

ice here, check out this one about

mind-bogglingly interesting crystal facts.

Thanks for watching folks, Don’t forget

to subscribe and we’ll catch you soon.