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[Music]

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hello and welcome to the 80th episode of

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technically speaking where scientists

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and Engineers come together to chat

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about common interest share knowledge

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and satisfy some curiosity as well as

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being the 80th episode this is the start

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of our fourth year in

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podcasting amazing I'm Antonia and in

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this Milestone episode I'm joined by

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Laura, Nick and Ellie to talk about

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explosions fire and some explosive

0:29

animals all way but we'll get to

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that so uh Laura you wanted to talk

0:36

about this why was

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that basically plutonium seems to be

0:41

portrayed in a very strange way in films

0:43

from what I can tell so normally someone

0:46

will say be careful with that it's

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plutonium and I get why the script

0:50

writers have said that basically to

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essentially get across that it's

0:54

plutonium they're working with rather

0:55

than something else but it always makes

0:57

it sound like if that person drops it it

0:59

will suddenly explode like it's I don't

1:02

know C4 or something and it's it's not

1:04

really true when it just winds me up so

1:06

there you go I want to have a bit of a

1:08

rant you drop C4 will

1:11

it that's what films portray I actually

1:14

don't know having never done anything

1:15

with it maybe we'll find out hopefully

1:17

we will because we have Nick here who is

1:22

a forensic engineer and you probably

1:25

could tell us a little bit about fire

1:27

and

1:28

explosions yes yes a bit so yep I'm my

1:31

name is Nick I am a forensic engineer I

1:33

investigate engineering failures and and

1:35

mostly a lot of fires um and as part of

1:37

that I investigate um quite a few

1:39

explosions including gas and chemical

1:43

explosions wow that's uh it's going to

1:47

be really interesting

1:49

to see what we can learn from you and

1:53

Ellie you are resident

1:56

zoologist and surprisingly animals fit

1:59

into this agree well this is what I want

2:01

your help with later on because I have

2:03

some examples and they are literally

2:06

called exploding animals so when I get

2:08

to it you can tell me what you think and

2:11

whether they're truly

2:13

exploding I think they are so I'm always

2:15

on the animal side let's read that by

2:19

now but it'll be it'll make a good

2:21

discussion point about what is and is an

2:24

explosive and how do they get their name

2:26

anyway so to start off with Laura

2:31

brought up the point about portrayals in

2:34

films

2:35

especially um

2:37

plutonium but we've seen a lot of other

2:40

types of explosions in movies and

2:44

sometimes you just think How likely are

2:47

they yeah so uh that be bear bearing

2:51

that in mind for example if you drop a

2:53

box of plutonium it's not going to

2:54

explode it's more

2:56

risk radiation there's a specific

2:59

mechanism of of course there I caus it

3:01

an explosion with PL plutonium which is

3:03

a bit out of my scope when it comes

3:05

thankfully to nuclear

3:06

explosions um as far as I know there's

3:08

not been a nuclear exp explosion in the

3:10

UK you know God willing there isn't

3:12

going to be one in the future but um

3:14

when it comes to other explosions such

3:16

as gas explosions a famous example being

3:18

of course um Hot Fuzz um if we all

3:21

remember that one of the murders in hot

3:23

f is committed by uh The Village Council

3:26

spoilers um opening all the um uh hob

3:31

rings on a on a hob in a mansion and

3:35

then leaving when lighting a match or

3:37

lighting a cigarette and eventually the

3:38

entire Mansion explodes of course in in

3:41

reality that won't happen at all for a

3:43

gas like methane which comprises mostly

3:45

of what natural gas comp comprises

3:48

mostly of you need a specific mixture of

3:51

gas and air to cause a combustion effect

3:53

to result in an explosion um usually

3:56

with methane gas you end up with

3:57

something called a deflation

4:00

um so it to basically from a hob you

4:03

need enough uh enough gas to be fed into

4:06

the atmosphere with a low enough

4:08

exchange rate so you get a high enough

4:10

concentration of gas for an explosion to

4:13

actually occur if that makes sense does

4:16

so

4:17

realistically if I left all my Hobs on

4:19

if they were gas the house wouldn't

4:22

explode if someone was just smoking

4:23

nearby No in fact if you left your Hub

4:26

on and your Hub was made in the last

4:28

five well no H if your Hop was made in

4:31

the last 20 years beg you pardon um your

4:34

gas would turn off as about 20 seconds

4:36

after you turn it on after due to a

4:38

flame failure device inside your hob

4:41

turns the gas off that's very reassuring

4:44

it is I'm pretty sure I've used Hobs

4:46

that are older than that yeah so Hobs

4:48

and heat older than that um they can

4:51

cause what we call a a a very small

4:54

flash or um tiny little explosion like a

4:58

warm effect um and then you C may you

5:01

may end up with like a bit of a a

5:04

flaming um vent but um but ultimately

5:08

for an explosion to occur you need a

5:11

large enough as I said a what we call a

5:13

a limit above what we call the l l lower

5:16

explosive limit um and Below U uh l u l

5:20

upper no u l u l the upper explosive

5:23

limit where you don't in sorry just say

5:25

the upper explosive limit it's all

5:26

methane there's no Oxygen you can't have

5:28

the combustion that causes the explosion

5:30

that's the problem you you do need that

5:32

oxidization that combustion to for the

5:35

explosion to actually happen if that

5:37

make sense yeah so really we're talking

5:40

about the fire triangle well we're

5:43

always talking about the fire triangle

5:45

but but some people are a lot closer to

5:48

fires than than you

5:50

than I'm not I'm never talking about the

5:53

fire triangle I didn't know there was a

5:55

fire

5:56

triangle yeah so a fire triangle

5:58

basically for any fire

6:00

or on the basic version sometimes we

6:02

talk about a fire tetraedron but we

6:03

don't talk about a fire tetrahedron um

6:07

oh my God I don't think I'm ready for

6:08

that let's start with a triangle let's

6:10

just for listeners for no reason at all

6:12

on a video feed I I'm holding my hands

6:14

in a triangle um we for for any for a

6:17

fire to occur you need three things you

6:19

need a heat you need fuel and you need

6:21

oxygen now usually for oxygen you've got

6:23

that in the air for heat that that's

6:26

usually where a a spark or a hot surface

6:29

comes in you need a fuel and in the case

6:31

of most explosions particularly gas

6:32

explosions that fuel is going to be

6:34

methane or some other explosive gas or

6:36

combustible gas I should say um so for a

6:40

fire or in this case an explosion to

6:43

occur um for example in hot F the the

6:45

fuel would be the natural gas um the uh

6:50

the heat would be from the cigarette and

6:52

the oxygen uh just from RE oxygen in the

6:54

General Air um all combustion and all

6:56

fire is a simple Chic reaction of

6:58

oxidization

7:00

resulting in heat and light and a

7:02

luminous um G gas we all call

7:05

Flames thank you very much and now look

7:08

at me learning things about explosions

7:10

already so if that's how a fire starts

7:14

then an explosion is something else

7:15

right and I'd think of it as you can get

7:17

like really volatile substances that

7:19

suddenly release load of energy kind of

7:21

what plutonium does and it explodes in a

7:25

certain environment so essentially it

7:26

has this kind of buildup of pressure

7:28

inside something that surrounds it that

7:33

releases yes exactly so typically an

7:36

explosion involving gas tends to be a

7:39

sudden expansion of of that gas so that

7:41

can occur in in a sort of a fire

7:44

explosion sense that's caused by the

7:45

sudden heating of the air suddenly

7:47

expanding um due to the combustion of

7:50

methane um in the case of I I worry

7:53

about treading towards a nuclear

7:54

explosion cuz my Nuclear Physics is is

7:56

wobbly at best where you can simulate an

7:58

explosion in if you over pressurize a

8:02

oxygen canister for example or a

8:03

canister of any any gas to the point

8:06

where the pressure inside uh reaches the

8:10

uh beyond the safe Li limit of that

8:12

container can hold and that if there is

8:14

a weakness in the canister that gas will

8:16

then explosively vent um a sudden

8:19

disruptive um Force blowing open the

8:22

canister and that will also cause air in

8:24

the room that canister has ruptured in

8:27

to also be pushed to the sides of that

8:28

as that the content of a canister is

8:30

also pushed out we often find no that's

8:34

not an explosion because it's not

8:36

violent enough is there a definition of

8:38

how violent it has to be that's the

8:40

movie classic as well they always can

8:43

always do like a shot like um Old Die

8:46

Hard where they like hand dramatically

8:48

across to the movie the oxygen canisters

8:50

for no apparent reason in an office

8:52

building andless yeah so all start to

8:54

steam and and you know the tops flying

8:57

off exactly exactly but of of course if

8:59

a top has flown off we've already

9:00

released the gas and it's fine there's

9:02

actually much that's just venting well

9:04

well precisely um for example if you if

9:07

you heat up a canister like that or

9:08

canister catches fire what tends to

9:10

happen is the safety me mechanism at top

9:12

breaks and it just Vents and catches

9:14

fire you know you have event I do with

9:16

this a lot um for listeners I'm waving

9:18

my hands around to imitate Flames flying

9:20

out of the canister yeah so we are so

9:23

you know you do so we've kind of

9:26

established you don't have to have fire

9:29

to have an explosion an explosion is

9:31

something different from a fire yes

9:35

exactly um in fire investigation it's

9:36

often the case it is a working out

9:38

chicken or egg what came first the

9:40

explosion or the

9:41

fire um and that forms part of that

9:43

investigation because often you'll have

9:45

a mechanical failure that results in a

9:47

gas explosion that then damages

9:49

equipment cause a

9:51

fire oh that that must be fun to pick

9:55

apart because at that point everything's

9:58

kind of spread out and

10:02

everywhere yeah it's fun but that that

10:04

can also give you information about how

10:06

the explosion C was caused and the

10:08

extent of the explosion which can give

10:10

you information about how much of it how

10:12

much pressure or how much of what kind

10:14

of material was involved based on

10:16

distances of debris for example or how

10:18

how blown out all the windows are or if

10:21

it knocked or if it blew out the side of

10:22

a house this sort of thing in in reality

10:26

um it's the case that you don't need all

10:28

that much pressure to cause this um that

10:30

level of damage for example um blowing

10:32

out the front of the house you just end

10:34

up with a lot of pressure points or

10:36

pushing on a wall at once which will

10:38

often overwhelm the structure and push

10:40

it

10:42

over ah so it's not so much an explosion

10:44

it's more of a just general it's a

10:47

mixure slightly too much pressure well

10:49

all explosion do too much pressure

10:51

that's just for nature of them yeah

10:53

slightly experiences may

10:58

vary um so yeah definition definitions

11:01

of explosions we we've somewhat covered

11:03

um in a in a fiery sense um the classic

11:07

in in fire investigation Kirks describes

11:10

describes explosions as a rapid oxid

11:13

oxidization with the evolution of

11:15

considerable heat accompanied by a

11:17

disruptive effect

11:20

well a disruptive effect what

11:23

understatement does it have to be

11:25

disruptive what if it is St what if an

11:29

explosion happen and no one was

11:31

Disturbed is it still an

11:34

explosion that's there's a tree falling

11:36

in the woods all over again that is a

11:38

good philosophical question I'll write

11:40

electus to Kirk and ask well yes

11:44

isly but is something to bear in mind

11:46

with explosions we always talk about in

11:48

a destructive effect but of course

11:49

explosions are in a controlled sense

11:51

very useful you know all combustion

11:53

engines work through tiny little

11:55

explosions in the Pistons or buff the

11:58

Pistons to push from up and down

11:59

and give us Automotion For Better or For

12:02

Worse I

12:04

suppose that is some technical stuff

12:07

that I think we'll be lost on people

12:08

soon now we're moving more to electric

12:09

vehicles I find that a bit sad Anno way

12:12

yeah that's true you're trying to get

12:14

your head around how an internal

12:16

combustion engine works I find quite

12:17

complicated with the four different

12:18

stages and I was going to say it blows

12:21

our mind a little bit but I feel like

12:22

I'm making a really bad pun you've got

12:24

to do it you have to make the bad

12:28

but has just occurred to me that it is

12:30

called a combustion engine

12:32

then leads on to the explosion idea does

12:36

like mini explosions to make your car go

12:38

forward that's why you have a spark SL

12:39

as

12:40

well that starts the Fire doesn't

12:44

it diesel cars don't have spark plugs

12:47

that's different isn't it I think we're

12:48

getting really distracted though I think

12:50

I don't think we need to go down the

12:51

internal combustion engine route anymore

12:52

do we I think we did an episode on

12:54

Turnal combustion engine as

12:56

well I think do they pretty sure yeah

12:59

diesel still has spark plugs um cuz that

13:02

that's the way so essentially all cars

13:05

all internal combustions engines diesel

13:07

or petrol work for the same principle of

13:09

you fine mist of um fine mist of liquid

13:13

into or vapor into the vapor of petrol

13:16

or diesel into the um combustion chamber

13:20

and then spark PL likes it and it lights

13:23

it and that little explosion pushes a

13:25

piston up and then it drops down again

13:28

and then the same thing happen again

13:29

then again that seems like it shouldn't

13:31

be

13:32

safe I know that it is and I know that

13:34

millions of cars drive across the world

13:36

every day but seems Seems

13:39

dangerous well it depends on your flavor

13:42

for safe if you just let it if if if you

13:45

just run an engine forever and ever like

13:47

that eventually it overheats so it needs

13:48

to be cooled and ventilated um so yeah

13:52

and also it breaks down over time every

13:54

little every little explosion causes a

13:56

little bit of damage and everything

13:57

wears down even in a control sense all

13:59

moving Parts fail

14:02

eventually

14:05

entropy another episode yeah we did ages

14:10

ago on thermodynamics

14:13

yeah but yeah I feel like um started off

14:16

saying plutonium and trying to have a

14:18

bit of R about it I feel like I should

14:19

kind of mention that in a bit more

14:20

detail so I've worked with quite a lot

14:22

of nuclear scientists over the years um

14:24

I don't know anyone that's tried to

14:25

build a nuclear weapon because I don't

14:28

work with those people

14:31

but the people that I work with that

14:32

have mentioned things to do with

14:34

plutonium is basically like you need

14:37

something called the critical mass you

14:38

need enough plutonium to make it do

14:39

something so similar to what you were

14:41

saying about setting up a fire say there

14:45

are various conditions you need to meet

14:47

to make your plutonium do anything even

14:49

vaguely

14:50

interesting um so just carrying it

14:52

around it's probably going to be fine

14:53

unless you've packed it into a certain

14:56

type of mass and have certain types of

14:58

plutonium is to ups and you've

14:59

surrounded it with the right amount of

15:01

moderator to reflect enough

15:03

neutrons to have a sudden massive

15:07

release of energy from the plutonium as

15:09

it absorbs neutrons it's just not really

15:11

going to do

15:12

much so in a film telling someone to be

15:16

careful unless you're trained on what is

15:19

safe and not safe is next to

15:22

meaningless so exactly what you were

15:24

saying about what you consider safe

15:27

neck what what does plutonium look like

15:30

like normally could you you can just

15:32

hold it with gloves on I know nothing

15:35

about plutonium so I really tree I've

15:38

never actually met any in real life I

15:40

think it's just like a gray metal there

15:41

are different types of plutonium though

15:44

I think it's like a in a all form it's

15:45

like a yellowy stone I know we call it

15:47

yellow cake for that's uranium uranium

15:50

ah mixing it

15:53

up but it's not by itself explosive it

15:56

doesn't have to be kept under like lock

15:58

and key

15:59

it

16:01

normal no it gives off neutrons some

16:04

isotop give off um alpha particles some

16:07

are more active than

16:09

others um so it's kept behind locking

16:12

key because people could potentially do

16:14

bad things with it yeah yeah and you

16:17

need to be trained on how to handle

16:19

it could you start a fire with it so you

16:23

might not have an explosion but you

16:25

could have a plutonium fire some form

16:30

do like to absorb water from the

16:32

atmosphere quite quickly which results

16:36

in quite a significant output of heat

16:39

which could potentially start a fire I

16:41

believe it's pyrophoric I think it's the

16:43

ter oh but I don't know any more

16:47

specific than that uh you can look it up

16:49

though if you want I think that

16:50

information is freely available

16:52

online that's a new word that I learned

16:55

pyro that's taken me right back to where

16:57

level chemistry that

16:59

I don't

17:00

know oops I'm going to say quite I I

17:04

think I've heard the word before but I'd

17:06

be I'd struggle to Define

17:08

it I I'll try to remember your

17:10

definition I think of plutonium fire

17:13

would be a very specialist uh

17:17

situation yes well on our risk

17:19

assessments we do have a radioactive um

17:22

option to tick

17:24

so Never Say

17:27

Never Go get my iron uh uh well my my

17:32

not my IR my lead PP on and off we go

17:36

iron he's just sticking on Armor yeah

17:40

this will help with radiation I'm sure

17:43

it won't hurt yeah there highly unlikely

17:45

though there are so many layers of

17:47

safety in place that getting to that

17:49

point is

17:51

just just probably having going to

17:53

happen in any realistic scenario here's

17:56

a layer of safety I don't understand

17:58

right I I was always told that you

18:00

weren't allowed to use your phone at a

18:02

petrol station cuz your phone could

18:04

cause spark that could ignite the petrol

18:07

and cause an explosion but is that

18:10

just uh over begging health and safety

18:14

or is that a legitimate

18:17

concern yeah so I I did look into that

18:20

uh a bit so I've not found an actual

18:23

source for the concern around using your

18:26

mobile phone while at with petrol

18:27

station other than being distracted Ed

18:30

um there is no source for mobile phones

18:33

causing electrical faults or any

18:35

electrical Sparks so I don't see why

18:37

they would need to avoid using a mobile

18:39

phone at at the pump other than of

18:42

course pay pay attention to what you're

18:43

doing and don't spill flammable liquid

18:46

all over the place ideally I suppose

18:49

flamable also is different to

18:52

explosive well then you oh okay so then

18:54

you run into a bit of a thing so um oh

18:57

no I've opened a can of flamable

19:00

worms well what what you'll find is what

19:04

all flammable liquids essentially if you

19:07

stick a match in a very very

19:09

specifically if you stick A Match Into

19:12

um a puddle of petrol u a match will go

19:15

out but if you if you wave a lit match

19:18

over the top of the surface of a puddle

19:20

of petrol um the vapors coming off the

19:23

petrol will ignite it's always the

19:25

vapors that ignite not the liquid itself

19:27

but you need as I said before you need

19:28

your fire triangle if you don't have

19:30

that oxygen you you've got no fire oh

19:32

that's a good

19:35

point so you can almost make too much

19:39

flammable if you just had only flammable

19:42

liquid it would be nothing but it's just

19:45

trying to keep oxygen away is quite

19:48

difficult on an

19:49

oxygen uh oxygenated Planet it it it is

19:54

it is so there's a there's an industrial

19:57

example I can BR up I've just had a

19:59

flashback from a a conversation I had

20:02

with a colleague during covid so well

20:04

not not quite during Co during that

20:06

period just when we were coming off

20:08

covid and uh people were starting and

20:10

fuel prices skyrocketed I think it

20:12

during the start of the Ukraine war um

20:15

and basically everyone was filling up on

20:16

petrol buying petrol while it was cheap

20:18

and a lot of there was just one person

20:20

who decided to fill up a load of of open

20:23

containers because they could be

20:25

Borrowed by a Jerry C and so we had two

20:29

uh I think four or five large um gallon

20:32

buckets of the back of their car um

20:35

filled with um petrol of course the

20:37

vapors coming off the these petrol um

20:40

fill the car and we I don't believe we

20:44

worked out what the ignition Source was

20:46

but the car exploded um not because the

20:49

petrol massive fire due to the petrol um

20:51

what we what as I understand happen was

20:52

a what we call defle regation where you

20:55

have a a a low speed explosion slower

20:57

than speed of sound um which blew blew

21:01

out the windows the driver was

21:02

apparently fine um but if you gather

21:05

enough petrol vapor in one place it will

21:07

combust and you will have a small

21:08

explosion similar to what you get with

21:11

meane vapor and gas are very

21:14

similar that makes sense I feel like all

21:16

these really dramatic explosions we see

21:18

in movies just they're not a thing it's

21:21

not surprising really movies make things

21:23

seem more dramatic than they

21:26

are yeah well we're

21:29

good pyro good pyro technques do present

21:32

really beautiful explosions with uh very

21:35

very directed with light and force as it

21:37

were um it's just not the same if

21:40

there's some action movie star running

21:42

away from a building going you know I've

21:44

saved everyone the building's about to

21:46

explode and then it doesn't explode on

21:49

the

21:50

H turn it all off it's just not the same

21:52

Vibe like Steven Spielberg is not going

21:54

safely as D no exactly but you know with

21:58

it makes our world a safer place and

22:00

explosions do still happen people do

22:02

still get hurt in them sadly um the

22:04

industrial example I was thinking of

22:06

thankfully again no one was seriously

22:08

hurt but it was a scenario where we have

22:10

a um a a chemical processing plant that

22:14

coats um Fabrics with solvents to make

22:17

them more water resistant and

22:19

essentially we have a situation where we

22:21

need to avoid a explosive environment as

22:24

the fabric runs through a roller and

22:26

that's Co in solvent and so so um they

22:29

put this uh the area this happen into a

22:32

high explosive protection area so we've

22:35

they've got a glass cabinet around it

22:36

and his ventilation making sure that the

22:39

solvent the dissolving solvent inside

22:41

Vapors coming off it never reach a um

22:44

never reach above the L Bel lower

22:47

explosive limit of the air air Vapor

22:50

mixture to cause an explosion and then

22:52

of course one day someone leaves the

22:53

door open um the L limit is moved Beyond

22:58

and then some spark most likely from

23:00

static um sets off ignites of gas and

23:03

causes an explosion knocking some s over

23:08

as he walked past the machine sometimes

23:10

it's a lot more is it it's easier to

23:13

prevent a explosive environment from

23:15

being created that prevent Sparks or um

23:18

other ignition sources from coming into

23:20

um the

23:23

situation yeah we've talked a lot about

23:26

Vapors and flam liquids but they're not

23:29

the only explosive environments you can

23:32

create you can also over press as you

23:36

can also over pressurize vessels to

23:38

result in an explosion we can also have

23:40

some examples I don't know if we want to

23:43

move into the animal examples

23:46

or no I was thinking dust and you know F

23:50

Powers although it I do often wonder um

23:54

I say Wonder think about these aspects

23:56

and they they are they follow a very

23:57

similar um pattern but you have a fine

24:01

particulate whether not be Vapor or um

24:04

powder a very F I don't know if you know

24:06

very famously windmills explode on a

24:08

disturbingly regular basis um because of

24:11

a fine dust powder fine flower that um

24:15

fills the air you can end up with a a a

24:18

dust explosion that results again in a

24:19

def regation pushing suddenly heating

24:22

the air and causing a um pressure to

24:24

push out and blow up well blow the

24:26

windmill apart is that just caused by

24:29

like friction between the dust

24:32

grains or something else so I've heard

24:35

so what's my well my understanding so in

24:39

truth um investigation into dust

24:42

explosions are relatively common whether

24:44

or not the grains rubbing together in

24:46

the air I don't see that I don't think

24:49

that would cause too much of an issue it

24:50

might cause heating but no that that's

24:53

that's the thing it's find us floating

24:54

around in the air so we'd be well

24:57

ventilated

24:59

well I think it's kind of it it makes

25:01

that it makes that explosive environment

25:03

it's got fuel because you know flour

25:08

dust is fuel for a fire you've got a

25:12

good a air fuel mix and then you just

25:15

need heat of some sort which could be um

25:20

I don't know if yeah I don't know if

25:21

it's the frictional you know static from

25:25

from dust but everything else you've got

25:28

is it St the

25:29

nice you've got two parts of the high

25:32

triangle yeah you just need a nice spark

25:35

a bit of friction maybe a door opening

25:37

someone touching something with a hand

25:39

and being earthed by it and little spark

25:41

and is part of the reason because the

25:43

dust creates this big surface areas

25:45

you've got a lot of the the fuel in

25:46

contact with the oxygen is that what

25:49

it's more

25:50

likely

25:52

yes exactly and you just need one little

25:55

uh one little um example of oxidization

25:58

cause enough heat to oxidize another um

26:00

particle of dust to oxidize another

26:02

particle of dust and then you have a

26:03

chain reaction that results in a sudden

26:06

um expansion of pressure due to come um

26:09

over a heating up so I'm sure I remember

26:11

being taught this in school and just not

26:13

understanding it at all 20 years later

26:16

now I do well but the scary the scary

26:18

thing is you can glad you reminded me U

26:20

you can do this with anything that

26:22

oxidizes so you can have um Iron fires

26:25

in the same way or um Titanium fires in

26:28

the same way um one of my colleagues

26:31

investigated not so long ago which

26:33

result in ex extremely hot um fiery

26:37

explosions maybe not so much um gasas

26:40

but definitely far

26:43

hotter wow

26:46

yeah oh yeah don't going to win M death

26:49

trap is that really likely though how

26:52

many windmills do we have making flower

26:54

these days I think there's only one or

26:56

two left in England I went to one

26:57

recently that's why maybe you think of

26:58

that maybe I wouldn't have gone in if I

27:00

it was extremely D I should point out

27:03

these aren't the wind turbines that you

27:04

see in fields and the offshore ones that

27:06

create electricity that's something else

27:07

entirely oh yeah these are like flower

27:09

based wind powerered

27:11

old buildings from way back when yeah

27:16

yes but I I think I think as as Antonio

27:19

was alluding to before that isn't just

27:21

the old style windmills you can get back

27:23

in any place you you process any Dusty

27:25

material um so flat any any modern

27:28

windmill with with flow they have a lot

27:30

of safety precautions to prevent um

27:32

explosions through um igniting the

27:36

flower in the air essentially could in

27:39

theory could I ignite flow in the air in

27:42

my oh yeah feel free oh well done we do

27:45

not I'm not going do this but we're not

27:49

but I'm just intrigued that if I threw a

27:51

kilo of flour around in my kitchen and

27:53

then lit a mat would it go up in FL I

27:56

remember it was a while go you can do an

27:59

experiment so you can get okay you might

28:02

want to edit this bit out so you you you

28:05

can get those little sucker things um

28:07

like a bigger one you use for getting

28:09

stuff out of children's ears and you can

28:10

suck up some some flower with it and you

28:13

can puff that into the air and you can

28:14

ignite

28:15

it you'll end up with a little wood

28:18

essentially yeah can do we not

28:21

advocating anyone do it inside their

28:23

home yes exactly quite interesting that

28:25

you could in theory yes exactly

28:28

exactly yeah dangerous dinner party

28:32

trick is you have candles on your table

28:35

you got some pepper and if you have

28:37

finally finally Mill pepper you probably

28:41

throw it across and little

28:44

Fireball yeah don't see why not except

28:47

for safety that's why that's why

28:50

not yeah no that's fair that's fair keep

28:54

it safe do it outside or

28:57

don't

28:59

we do not want to be sending Nick to

29:01

investigate what caused this

29:02

fire he'll know you'll listen to the

29:06

podcast one sec is that a bag of

29:10

flour and a weird sucker

29:13

thing

29:15

Technic that sounds like a good lead in

29:17

for exploding

29:19

animals yes any sucker related animals

29:22

that

29:24

explode no suckers I'm really intrigued

29:27

what you guys are going to think about

29:28

so we're going let's start they're all

29:31

insects so they start with turn m going

29:33

to move to an and then I've got a

29:35

special bonus one for you at the end I'm

29:37

nice like that is this going to be like

29:40

a quiz

29:41

Al we could do a quiz but maybe not um

29:45

so this is a species of termite in the

29:48

rainforests of fren

29:51

Viana and they grow sacks of toxic blue

29:55

liquid on their backs like little

29:59

termite and then they explode these onto

30:02

their enemies in suicidal self-defense I

30:06

mean is that just not the coolest thing

30:08

you've ever heard how do they make them

30:10

explode like a bucket of

30:12

paint how do they make you explode I'm

30:14

very glad you asked that question Laura

30:16

so they filled their backpacks with blue

30:18

crystals which are secreted by glands on

30:21

their

30:22

amb and

30:25

then they I think this is the one where

30:28

they tear into their bodies oh no this

30:31

is the this is the squeezy one they

30:33

squeeze their abdominal muscles so hard

30:37

until they

30:38

explode and they have a portion of their

30:41

abdominal wall which is thinner and

30:43

weaker that is like primed to do this

30:47

and then yeah it like explodes

30:50

the contents on their enemies in and

30:53

they die you see because they raptured

30:55

their own abdomen is this exploding

30:58

bursting oh this is the kind of content

31:02

did but that's a fair point my

31:03

description of a over pressurized vessel

31:07

that's essentially bursting that's what

31:09

I was wondering is yeah the cre is a

31:12

water balloon an explosion or is it just

31:16

bursting excellent well

31:19

made well well then again the water does

31:22

not expand out in every dire or every

31:26

direction it well I suppose it goes in a

31:29

specific does didn't you say there had

31:30

to be an increase in as well Nick to

31:33

count as an explosion so it for a a a

31:38

fiery explosion certainly but an over

31:41

pressurized exp and again because of

31:43

pressure you know the increase in

31:45

pressure does tend to be a result of

31:47

overheating we call those

31:50

mechanical you can straight up have a

31:52

mechanical explosion like if

31:56

you if youum filled a balloon with a an

32:00

O and popped it that is that not an

32:05

explosion as well and mechanical one I

32:08

say pop I mean you know cause the

32:11

balloon to rupture like these termites

32:15

yes thank you would you say on the

32:17

termite would you say would you say it's

32:19

still included the disruptive

32:22

effect oh it's definitely disruptive if

32:24

you're a you know an invasive Predator

32:26

against these T lights I think this

32:27

might sway you okay so they've got a

32:30

chemical reaction going on as well on so

32:33

they've got two specialized glatts uh

32:36

and they produce these blue crystals but

32:38

then when the termites explode there's

32:41

extra pouches that burst the salivary

32:43

GRS and the crystals have to react with

32:46

the secretions of the civr to become tox

32:50

so there is an extra bit of something

32:52

going

32:53

on yeah although it does sound like

32:56

we're spraying them with toxic cryst

32:57

Crystal which granted I wish I I wish I

33:00

could spray my enemies with toxic

33:02

crystals I wish I had glands that made

33:04

toxic

33:05

crystals but uh I know naing and it is

33:09

quite

33:10

disruptive it' be pretty dis especially

33:12

for the lives of the termites that are

33:14

exploding they're they're dead so it

33:16

doesn't get more disrupted than that

33:18

yeah I can't help but feel though just

33:20

based on my experience a good definition

33:23

an of an explosion is a sudden and I got

33:27

to say disruptive expansion of gas

33:30

essentially that applies pressure

33:31

somewhat equally around in all

33:34

directions if that makes

33:36

sense um it's similar to an implosion

33:39

where you have some everything that

33:40

sucks in an explosion is the opposite

33:42

there um the gas in that are is all

33:45

pushed out in all different directions

33:48

different direction of least resistance

33:50

case tends to be yeah it just about to

33:52

say you get shaped explosives for

33:53

helping with um demolition projects

33:56

which suggests that the force is

33:57

directed in a

33:58

particular place not just expanding in

34:01

all directions but I guess that comes

34:02

down to what you were saying so he bites

34:04

around it with something on one side

34:06

that directs the explosion somewhere

34:08

else yes well demolition explosions tend

34:11

to use um uh what we call High

34:14

explosives to do high high level very

34:18

powerful but small explosions in very um

34:21

specific directions I wasn't sure Ellie

34:24

earli on did you ask if you dropped a

34:25

box of C4 will it explode yes I did ask

34:28

that yeah so if you drop a box of C4 it

34:30

won't

34:31

explode okay because I mean I'm very

34:33

clumsy for that it's good to know but I

34:35

don't think I ever be carrying SE yeah

34:37

um you you need specific trigger to as I

34:40

understand typically I'm not a

34:41

demolition expert but uh you need a a

34:44

spark or specific igniter to cause um C4

34:48

and specific modern explosives to

34:50

explode older um explosives such as n RS

34:54

made using nitr is it nitrate

34:56

nitroglycerin um that tends to be that

35:00

tends to be fairly unstable um and can

35:03

explode if if um sufficiently rustled

35:06

about essentially um due to sudden

35:09

oxidization from small um from small

35:11

amounts of heat caused by the disruption

35:13

as I understand but no one would use

35:15

that anymore because it's it's a bit too

35:19

uncontrollable

35:21

yes Al Never Say Yeah it depends what

35:24

you're trying to achieve and here you

35:25

are I suppose comes back to my point

35:26

about plutonium in films it's criminals

35:28

trying to steal

35:30

it yeah is I feel like we've distracted

35:34

you Ellie from uh animals I know get

35:37

back not come to a

35:40

conclusion there's another species of

35:42

ant so this instead of we're moving from

35:44

termites to an and it's literally called

35:46

hopsis

35:49

explodens uh because it's explosive and

35:51

it is similar to the termite and that it

35:54

flexes so hard that its abdomen bursts

35:57

at the sea and they tear themselves

35:59

apart to protect the rest of the colony

36:01

they literally explode themselves by in

36:06

selfdefense and also you said about G uh

36:09

while these ones apparently smell

36:12

strangely of Curry and they explode

36:14

there must be some sort of gas release

36:16

going on there as well

36:17

oh if it's C

36:20

in yeah I never mind

36:23

um yeah well possibly so is there any

36:26

sort of this sounds similar to again

36:28

similar to a bursting but for chemical

36:30

reaction R does that usually result

36:32

in um burning or uh sudden expansion to

36:38

knock the um prey

36:40

away um is to cover them in a toxic

36:44

fluid gotcha no so they explode and

36:47

release this bright yellow sticky

36:50

substance gotcha what's it smells like

36:53

here's my question what's the like

36:56

radius you know the blast

36:58

Zone retin it is it far enough that it

37:02

could be an explosion not just they

37:04

leaked a little bit of toxic uh

37:08

liquid I really don't know but also

37:11

remember that it's an an so like

37:13

realistically it's not that but relative

37:16

comparative

37:18

down well if it didn't work they

37:20

wouldn't have evolved over millions of

37:23

years of evolution to do this right so

37:24

it must be a large enough radius they

37:26

can protect poon from whatever's coming

37:28

towards and if two species are doing it

37:30

are they evolutionary linked in any way

37:32

the ants and the termites I don't know

37:34

why You' know that but it seems logical

37:36

to me they must have had a common

37:38

ancestor they must have had a common

37:40

ancestor they're too similar aren't they

37:42

they're

37:43

too they got too much in common unless

37:46

it's remarkable convers it does happen

37:49

sometimes doesn't it because if if it

37:50

works for one species in one environment

37:52

you can imagine another one might evolve

37:53

it in a completely different environment

37:55

and they'd be totally unrelated there

37:57

many examples of convergent evolution

37:59

where species that aren't actually

38:01

related by a common ancestor have

38:03

evolved these same traits like the

38:05

exploding an and ter lights even though

38:07

I reckon they probably do from ancestors

38:09

somewhere way back in the evolutionary

38:12

history but also because you were

38:14

arguing it that it's not actually an

38:17

explosion it's a bursting at the sea but

38:19

what about something like the Hulk

38:21

because when he is Bruce Banner that's

38:24

the character right and then he becomes

38:26

the Hulk he bursts out of his own body

38:30

and he like rips all of his clothes is

38:32

that an explosion or is that just

38:34

something

38:36

else we you could make the argument

38:38

about it's an explosive expansion of

38:40

banner um you know similar to an

38:44

explosive expansion of of gases in a

38:47

caused by

38:50

combustion b i I'd say bursts and

38:52

explosions are similar explosions in a

38:54

fire investigation sense always involve

38:57

uh some

38:58

um combustion oxidization of gases I I

39:01

must admit maybe saying that bursting

39:03

doesn't count as

39:04

exploding isn't isn't exactly Fair

39:07

because you

39:09

know I'm taking it as a win for the I'd

39:12

say it's definitely a mechanical

39:14

explosion we'll call it a biological

39:17

mean bi mechanical explosion there if I

39:19

make yeah there's chemicals involved

39:21

than this

39:22

[Music]

39:23

one but I I I'd still encourage just one

39:26

just one more thing in animals causing

39:28

what I'd argue is more of an explosion

39:30

pis pistol pistol crab a crab with a

39:34

giant claw that has is able to close the

39:37

claw so quickly with such pressure it

39:39

causes a burst of water at high pressure

39:42

to shoot out of it and how it's Hunter

39:44

spray I think it's have you heard before

39:46

I think it's a species of shrimp yeah

39:48

and it's like is it sonification where

39:51

it causes light the reaction light as

39:53

well that's correct

39:55

ter there we go so we've got

39:57

got got light and high pressure perfect

40:00

and it's a really hot CL from just one

40:03

mechanical movement or is the light

40:05

produced by a chemical yeah it's so

40:07

incredibly fast and the force is like

40:11

wildly wildly high this tiny little

40:15

animal there's videos of it doing it

40:17

really and there's a

40:23

FL I have one last

40:25

example this is I think bit of a

40:28

schoolyard joke perhaps and I normally

40:31

wouldn't say that but it's quite

40:35

funny um so the the situation is that

40:39

when a male honeybee mates with a female

40:42

honeybee his testicles explode and he

40:45

dies hilarious why would it do that yeah

40:49

evolutionary why would it help evolu

40:52

then no there's always an advantage so

40:55

basically his Endo phalus which is

40:58

basically a BPS is then lodged in the

41:02

female preventing another male from

41:04

coming along and mating with the queen

41:08

bee ensuring that his genes are passed

41:10

on think how many offspring a queen bee

41:13

would explosive reproduction it's

41:15

incredible apparently it's also Audible

41:18

for the human ear if you were

41:21

nearby I think I think that' be a good

41:23

example of an explosion you know similar

41:26

to what we discussed prev viously you

41:27

know a biomechanical

41:30

one well it's also I don't know if it's

41:32

like a ripping more than an explosion

41:35

because his endal is ripped from his

41:38

body but I think there is some buildup

41:40

there must be considerable Force

41:42

otherwise how's it

41:45

stop yeah or is it like a cork screw

41:48

like some animals have cork screws to

41:50

kind of make it more difficult

41:53

to get away from the ra that

41:58

yeah yeah there's a lot of techniques

42:01

like that sort of thing to prevent other

42:03

males from Bing female in the animal

42:05

kingdom is interesting but Snopes did a

42:09

review on it because it's one of those

42:10

things that gets like banded around and

42:13

they reached out to a number of experts

42:15

to confirm whether test R and they they

42:18

reckon it's correct they couldn't say

42:20

100% one way or the other so they said

42:22

it's a research in progress at the end

42:25

of their article I was just wondering

42:27

yeah how would you observe that how many

42:30

bees do you have to watch me to be 100%

42:32

sure but they also die this is the this

42:34

is the trade off with exploding animals

42:36

the termites die the ants die

42:38

unfortunately the males bees die when

42:41

part of their body

42:43

explodes so is a lot of this just

42:45

inferred from the apoma similar to job

42:48

as a parens we've linked it full

42:51

precisely amazing it'll be deaths yet

42:54

but I'll let you know as soon as I come

42:56

across one

42:58

if that caused a fire that you had to go

43:01

investigate how many bees would that

43:03

have to

43:06

be I'll get back to you on that one I

43:09

don't think bees are small enough to

43:10

cause a um a dust explosion R so we'll

43:14

see we'll see a devastating effect

43:16

exactly thousands of casualties B

43:18

casualties

43:22

on they just I don't know how that would

43:25

happen explode whil surrounded by pollen

43:27

in the hive that is a ridiculous kind

43:30

get quite warm though can't they they

43:33

like inside the hive it can get really

43:35

warm inside a hive but I think that's

43:37

more body heat and Hive engineering than

43:40

it is

43:42

Uhl

43:44

yeah so we've not seen any exploded

43:47

beehives not

43:50

yet not yet natural causes I mean if

43:53

they get Dusty perhaps I don't I don't

43:56

want I don't um B

43:59

aren so someone who desperately hates

44:03

bees I can't leave the bees alone we

44:06

need the bees I can't think of a

44:07

mechanism which cause a hive to explode

44:10

and ultimately that you do need

44:11

mechanisms for these things to

44:13

happen good well I'm glad that's scene

44:16

in um H games where she cuts the hornet

44:19

nest off

44:23

the is that an explosion or is that just

44:25

a burst that's a bursting the bees an

44:27

explosion of Anger from the

44:32

bees so it seems like a good place to

44:35

leave it we've deviated quite off topic

44:38

we started off with Laura's rant about

44:42

how

44:43

plutonium is handled very delicately in

44:46

films when in fact if you dropped it it

44:49

probably would not cause an explosion it

44:52

would cause other bad effects but

44:54

probably not an explosion but we then

44:56

also learned about what is an explosion

44:58

and how do you hopefully not start one

45:02

um

45:04

and the animal kingdom is explosive

45:07

apparently thanks for listening and see

45:09

you in the next one avoid windmills the

45:12

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45:14

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45:15

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[Music]

45:31

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