Mythbusters : quel est votre problème ?

- Never try anything you see on the show at home.

Well, there's your problem.

- In this special series of MythBusters.

It's almost too exciting.

- The dream team tackles their dream themes.

It's scientific

- Testing myths about everything

from electricity.

Ow!

To pressure.

Whoa!

And gravity.

This one hurt a bit.

Whoa.

- Shaking down the science of shock waves,

velocity

and ballistics.

Hahaha

With crazy chemistry.

Oh my goodness.

Far out physics.

Fun for the whole family.

And insane explosions.

Is everybody okay?

- Life's burning questions answered

on MythBusters "There's your problem".

On this episode,

It's burn baby burn.

As the teen tests out myths about fire.

Whooh!

This is gonna be scary.

While later they do a 180.

It's time to go to war.

And get to grips with ice.

Come on baby.

It's a feverish ride

That's beautiful.

- As temperatures hit new highs and lows.

First up,

viral myths and MythBusters,

they go together like C4 and explosions.

Whoa, that looks seriously dangerous.

I like it.

You know they're claiming to do this

with only sawdust.

Fans; they're a little skeptical.

They think it's either something way more flammable

or it's CGI.

Well, in theory it could work.

Yeah, even though they say

they're not using any accelerant,

if the powder's fine enough,

you could get that result from just sawdust,

compressed air and an open flame.

Oh, we are gonna have to be so careful.

- Viral videos can sometimes be a little

loose with the truth.

And viewers have suggested

this may have involved added accelerant,

but the maker says not.

What we have here is the energy source,

It's a propane tank.

- All you need is compressed air, sawdust

and an ignition source.

Time to test if this is for real,

to make the sawdust Cannon Barrel

Kari recycles an old pipe.

- Well you didn't want it to come all off in one piece,

did you?

- Grant works on an empty propane canister,

just like in the video

modified to hold compressed air.

A high flow valve should release it all into the cannon

in one short blast.

When we push this button,

it deploys in less than a quarter of a second.

- Heavy duty pipes connect the canister to Kari's cannon

and it's ready for a proof of concept blow test

without flame to see how high they can blast the sawdust.

- I think this will work out pretty well.

It's light and fluffy.

The canister is pressurized

to 100 PSI and.

In 3, 2, 1.

That's good.

The problem is it didn't go that high.

No,

10 feet in the air.

- At the moment It's not looking exactly like the height

that we would expect to see.

Um, no, not quite.

But I think it's achievable.

So what to do?

Grant thinks he'll get more punch with less hardware.

He fits a shorter connecting pipe,

then carry trims an inch or two off the legs.

Scarface belleci's already booked the bomb range.

Say hello to my little friend

Where they get ready to blow.

- So this orange line right here is connected

to the air compressor

and that is the source of air for the whole cannon,

and hopefully that'll be enough to create

a huge sawdust plume.

- The plan is I'm gonna light the flare.

Grant's gonna pull the string,

and hopefully we'll get a giant tower of fire.

- The pressure inside the canister

rises to 120 PSI.

Perfect.

Good to go.

In goes the ignition source.

Alright. 3, 2, 1.

Grant releases the compressed air.

Oh my God.

That was the coolest thing I've ever seen.

It didn't look like it was gonna ignite,

and then all of a sudden, Whaw!

It went up.

It was beautiful.

- It's not just the size of the flame, but the sound.

Whooh!

It was amazing.

- It's a towering inferno of nothing

but sawdust, tiny particles which burn instantly.

When one particle catches fire, it ignites the next,

almost immediately causing a rapid chain reaction

better than the original.

It was way cooler.

- With a potential hoax definitively unhoaxed,

what next, but to up the ante?

So we made our canon to the specs

of the video and it worked.

Now it's time we ramp it up and we make a giant canon.

And see how big we can make the fire!

- They've clearly caught the fire bug,

Kari included.

She wants something more combustible than sawdust,

so she tests other fine grain substances like flour.

That was good.

Next, non-dairy creamer,

which is made from highly combustible corn syrup,

- Non-dairy creamer, flame burns to my hand

and into the cup.

It's so flammable that there is a back draft.

- They found their most flammable fuel.

Meanwhile, Tory's increasing their firepower.

He's turning this blue hopper into a launch cannon

and welding on a 55 gallon yellow barrel.

Huge pipes will dump compressed air into the cannon.

And let's not forget to pack the fuel.

- How big a cup of coffee do you think you need

for 3000 pounds of non-dairy creamer?

Back at the bomb range,

the coffee creamer is loaded into their supersized cannon.

All right. It's full.

Everything is set.

So what's the prediction?

- First of all, we know that the non-dairy creamer is much

more reactive in air than the sawdust.

Second, the orifice size is much larger.

36 times the force, 20 times the air capacity.

If everything goes right,

we can set this whole hillside on fire

As the saying goes.

Careful what you wish for.

We're good to go.

Tory sets the spark

and they beat a rapid retreat.

Okay.

All right, fire this puppy up.

Here we go.

Non-air creamer, cannon in 3, 2, 1.

Yeah!

That was frightening!

Terrifying.

This was frightening.

I mean, seriously.

There was a moment where I'm like, oh crap,

this was a bad, bad idea

When you set off an explosion.

Whoa my god!.

You click boom.

When you fire one of these cannons,

you go click,

you're like, Whoosh.

Ah, it's not working.

Oh my god, it's up.

All I heard in my head was run.

We should destroy this.

This technology should not be shared with anyone.

- And just in case you missed the message,

I hope I don't need to tell you this,

but don't try this at home.

- Now, a fiery face off to warm the cockles