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  • - If you did this in a movie theater

  • and had the actual explosion force

  • from C4 going off, you'd have to have a big sign

  • that says "Put in your earplugs now."

  • [explosion]

  • - Remind me not to come to your movie theater.

  • [laughing]

  • [fire crackling]

  • - Jesus Christ!

  • [dramatic music]

  • [explosion]

  • - Hi, I'm Paul Worsey and I'm a professor

  • of explosives engineering.

  • - And I'm Tassilo Baur, a special effects supervisor

  • in Los Angeles.

  • - Today, we're going to review explosions

  • in TV and film from a scientific perspective

  • - And a filmmaking perspective.

  • - "Desperado." [gunfire]

  • [upbeat music, gunfire]

  • - Jack?

  • [upbeat music]

  • [explosion]

  • In the guitar case, we see some modern-era grenades.

  • But unfortunately, they're rolling around.

  • And that's not the sort of thing I'd want

  • to do with grenades is have them rolling around,

  • bouncing into each other.

  • Now I personally wouldn't throw a guitar case full

  • of grenades at my girlfriend.

  • These look like wire-round grenades

  • inside those casings rather than a segmenting grenade.

  • The original grenades were pineapple in design.

  • And they were supposed to break up into large chunks.

  • And that was the idea on them.

  • And these large chunks were propelled out and killed people.

  • Modern grenades are designed to give a lot of fragments,

  • very small fragments which are termed frag.

  • The term shrapnel is usually used accidentally

  • instead of frag in a lot of films.

  • And shrapnel actually is ball bearings.

  • And there was a shell called the shrapnel shell.

  • And it was invented by Mr. Shrapnel.

  • So, in a shrapnel shell, the ball bearings are there.

  • And they're blown everywhere by the explosives.

  • Frag comes from a steel casing that's broken.

  • It's turned into pot metal by the detonation wave.

  • And then these small pieces fly everywhere.

  • They're sharp, do a lot of damage.

  • In a lot of movies, somebody will throw a grenade

  • and you'll see a huge fireball.

  • And that's not really realistic

  • unless they set off a propane tank that's just off-frame.

  • A frag grenade when it goes would be a poof,

  • a rather large bang,

  • but you definitely won't see a lot of flame.

  • - To create that effect,

  • they would have placed explosives specifically

  • with a view toward causing that wall of fire.

  • And the grenades of course are simply props

  • that the stunt performers on the ground react to.

  • To create this explosion,

  • they probably would have used gasoline lifted

  • by charges placed between the two buildings.

  • You can even see in the top right corner part

  • of what seems to be the bag

  • that the gasoline was likely poured into.

  • Then there's a smaller explosion

  • where they're flung away from it,

  • which is probably done with an air ramp

  • or something to allow them to jump the way they do.

  • And then we see the wide shot of the two main actors

  • against a fireball and it's done very cleverly

  • in that there's really good protection for them

  • and of course, it's on a long lens

  • to compress the distance between them and the fireball.

  • The fireball is actually between the two buildings.

  • So it's basically going up like a wall

  • instead off billowing out like a mushroom.

  • So other than the radiant heat,

  • there's really no risk to them.

  • And they're good actors so they don't flinch.

  • They carry it off and it makes a great shot.

  • [upbeat music]

  • - [Paul] "Batman."

  • [dramatic music]

  • [hissing, dramatic music]

  • [panting, dramatic music]

  • - Meow.

  • [explosion]

  • - In this sequence, we're seeing a lot more complex effects

  • than just the explosion.

  • First off, the Catwoman performer punches

  • through the metal door to the cabinet.

  • And the metal door to the cabinet,

  • obviously, would have to be prepared

  • in such a way that this performer could punch

  • through it safely and it would look like it was supposed

  • to when it broke.

  • This sort of thing is what's called a breakaway.

  • And frequently it's made so you can replace it quickly.

  • So you can do multiple takes.

  • Once she rips it open, we then see her break the gas line

  • and gas escaping and there's a sign there that says "gas."

  • But just to show us visually what's happening,

  • there's a substance streaming out of the broken line.

  • The time the film was made, that was probably freon,

  • a component of air conditioning systems.

  • Unfortunately, that has ozone-destroying properties.

  • So currently, we would probably use something

  • like liquid nitrogen or liquid CO2

  • to create a visible jet of gas.

  • Then we see her put spray cans into the microwave

  • and start it, which then appears

  • to trigger the larger explosion.

  • - Whether this is realistic or not,

  • I think it looks really, really good.

  • And I've seen a lot of gas explosions

  • and they can look quite spectacular.

  • This is what happens in people's house sometimes

  • that the gas escapes and it builds up

  • in the house and it builds up slowly

  • to the lower end of the explosive limits.

  • And then there's a spark of some sort

  • and that's all it takes.

  • I would expect personally to see a little bit more

  • of a blue color to it.

  • When you do combustion, if you're on the lean side,

  • it tends to be a little bit blue.

  • And if you've got too much fuel in there,

  • it goes on the yellow side.

  • - To manage the risk in this explosion,

  • they used very cleverly a series of different ones.

  • First off, you see the real performers

  • in the configuration in front of a building,

  • which probably had no explosives in it

  • to set up the geography of the shot.

  • Then you see an over-the-shoulder shot,

  • with what is very likely a stunt performer

  • as Catwoman, which is convenient

  • because she happens to be a wearing a costume

  • which lends itself toward that.

  • And that later you see a much wider shot

  • where there are no performers in the proximity

  • to the explosion at all,

  • which they can have a full-force explosion.

  • So they go from no explosion to smaller explosion

  • to a huge explosion and by cutting them all together,

  • it creates the illusion

  • that the performers are right next to it.

  • The over-the-shoulder is clearly shot

  • with a very long lens with a view

  • toward compressing the distance

  • between the explosion and the performers.

  • Very successfully it also makes the shot more dramatic.

  • The other thing that they will tell stunt people

  • to do is move a little bit or they'll think you're a dummy.

  • Humans are looking for human characteristics.

  • That's why they'll very often have the stunt performer make

  • some sort of small movement leading

  • into or reacting to the explosion, even if it's minimal,

  • just to show you that it's not a dummy.

  • - In a real explosion, okay, there's gonna be a shockwave.

  • And that will cause things to move, okay.

  • I have some footage underground

  • where we have our explosive camp

  • for high school students and the campers are there.

  • And we shoot dynamite about 100 foot down the tunnel.

  • All that force comes towards them.

  • And what it'll do is it'll blow their hair all

  • over the place on the girls and the pant legs

  • on everybody will flap backwards and forwards.

  • And sometimes if you use enough,

  • it'll knock off hardhats if they're in just the right place.

  • So it's quite an experience.

  • [explosion]

  • - [Tassilo] "The Dark Knight."

  • [explosions]

  • This was a real building demolition done

  • for the movie actually on a real building

  • that was scheduled to be demolished in any case.

  • - [Christopher] We blow up a lot

  • of different things in this film.

  • And with our major explosions,

  • I was determined to do one of them for real.

  • - It's very important as special effects people

  • that we keep current and enhance our skills

  • to the degree that we can,

  • but it's also important to know our limits.

  • Building demolition people shouldn't do special effects.

  • And special effects people

  • shouldn't do building demolitions.

  • It's apples and oranges.

  • In this case, you have two separate disciplines working

  • together to create this overall effect.

  • - We're working in very close conjunction

  • with Chris and his crew.

  • So they'll have their special effects going off.

  • And it won't interrupt our demolition charges.

  • - On the demolition side, I can tell you exactly

  • what happened.

  • The windows start to reverberate and shake.

  • And that happens roughly five seconds

  • before the building actually starts to fall.

  • And those reverberations are made

  • by detonating cord going off inside the building.

  • The actual concrete columns inside

  • that building will each have had say three

  • or four explosive charges,

  • which are actually drilled into the concrete.

  • Then they're wrapped with chain link fence and geotech.

  • - All of this material is to prevent any debris

  • from flying out of the building when we blast.

  • - So that stops all that concrete flying everywhere.

  • And when you blast that pillar,

  • what you wanna do is you wanna turn

  • that concrete into its original ingredients,

  • which is lime, sand, and aggregate.

  • And what happens is it gets blown off the rebar.

  • And the rebar inside the concrete is just like a string.

  • And it gives the concrete tensile strength

  • and bending strength but as soon all that concrete has gone,

  • the actual rebar gets pancaked.

  • - The debris is handled very effectively

  • in this particular sequence because we want the talent

  • to be close enough to the explosions

  • to tie it together without subjecting them

  • to a great deal of potential risk.

  • As you notice, before things get really serious,

  • the talent is all inside the bus,

  • which probably has the windows replaced

  • with something that doesn't break,

  • some sort of polycarbonate or something.

  • So they're really well protected in there,

  • not only from debris, but from sound.

  • As Dr. Worsey pointed out, all the stuff is contained

  • by the chain link fence and all these precautions

  • that are taken.

  • You don't get that debris flying off.

  • So what we supply is lightweight debris that's controllable.

  • It flies off in a visually spectacular way

  • and enhances the effect.

  • From looking at some of the behind the scenes images,

  • you can see that the debris mortars were actually,

  • as is common, firing pieces of cork and lightweight debris.

  • And the metal drums were probably filled

  • with a combination of gasoline

  • and something else to make it more visually interesting,

  • which then creates the fireball.

  • - And with all those explosions going on,

  • he doesn't lose it for one iota.

  • Just the perfect performance.

  • - You can make the actors as safe

  • as they can possibly be, but if they don't feel safe,

  • it's gonna affect their performance.

  • Joker doesn't care about any of this.

  • He's completely nonchalant and if he hadn't felt safe,