## Friday, February 27, 2009

### Carrying stolen money

There was a bank raid this morning where an bank employee was made carry 7 million euro out of a bank. The story is here

"The official, who is in his 20s, was then forced to drive his car to the bank. After withdrawing the money, he handed it over to the gang at Clontarf DART station."

I am ignoring the horror of the attack and just asking what would 7 million euro weigh? In 2 euro coins it would weigh 29750kg

A bank note is around 1 gram according to here.
So 7 million euro is
14000 500 euro notes (1.1g) or 14.4kg.
100 euro notes (1g) are about 5 times that 70kg which a normal man could not carry nonchalantly out of a building.
50 euro notes (.9g) would weigh 126kg which most people could not lift.

So how did the employee carry this money? You would think there would be restrictions on employees carting large bags of money around.

There is also the size issue. 500 notes are Size: 160 x 82 x 0.12 mm so 14000 would be a pile 168 cm high. So say you want to put these into a duffel bag. This is roughly 600 mm long by 300 mm wide by 300 mm high

So you can fit three pile lengthways, three sideways and 2500 notes upwards. So in a duffel bag you can have a bit more then (there is left over room at the top and sides) 3*3*2500= 22500 500 euro notes. This is 11250000 euro weighing about 25 kilos.

How many 100 note (1g) of Size: 147 x 82 x 0.12 mm, 50 note (.9g) of Size: 140 x 77 x 0.12 mm could be carried?

### Nuclear war 2.0

In the latest in my increasingly unhinged worries about nuclear war I started wondering what would happen if someone accidentally spilled coffee into the wrong machine and it did all kick off. Off course there are so many back ups no such accident could happen like the way a drunken depressive could never be the one with the final say on when Armageddon comes...

Anyway if they did launch what would be the effects on your house?

Turns out some people have already made a shinny web 2.0 app that lets you see this

Its great family fun to play around with. Center the flag on the nearest location you think will be nuked and have a look at the various effects. You can go for that retro 50's bomb, the humongous 60's version, all the glamour of a modern small tactical nuke.

Playing with these toys the maps and the nuke computer and such is a really odd feeling. Part of me is impressed with the sheer Promethean hubris of the enterprise. Its hard not to admire the technocrat logic of the slide rule nuke computer the shiney mashup of the nuke map or the eery idea of subs wandering round blind in the ocean. Mainly though I wonder how I got stuck on this planet that is clearly packed full of psychotic apes.

## Thursday, February 26, 2009

After doing all the calculations for the chances of submarines wandering around blind filled with nuclear weapons crashing into each other i got a bit scared

There is something painfully absurd about the idea of blind mute spheres of death wandering round the oceans hoping not to bang into each other.

We like to think nuclear war was only a problem around the time of Bob Dylan's first album and was shot in kodachrome photos but the fact is it could still kick off today.

"I did a preliminary risk analysis which indicates that relying on nuclear weapons for our security is thousands of times more dangerous than having a nuclear power plant built next to your home."
Diffie

So for fun why not compute like it was 1962 and see what would happen if various nukes went off in your vicinity. There is a fun print and make Nuclear Bomb Effects Computer here and some more here. They are basically versions of slide rules people used to calculate how big fire balls and such would be.

Hey get the kids involved, its crafty and its edumacational. Why not teach them about how close to a bomb they would need to be so that all that would be left is the enamel of their teeth?

## Wednesday, February 25, 2009

### Submarine Collision Probability 2

Suppose submarines were spherical particles just wandering round the ocean. Occasionally they would hit the shore its surface or its maximum depth and would bounce off and head away again. Submarines do not move randomly but they do not follow fixed ordered paths either as that makes them easy targets.

The submarine was modelled as a cylinder of length 140 meters and radius 6 meters so it has a volume of 63360 meters cubed. If this is instead seen as a sphere this volume would have a radius of 24.73 meters. Forgive the spherical cow nature of this sum. From a previous calculation you have 25 particles (submarines) of volume 63360 cubic meters each in a space the size of 300 million cubic kilometers. How often will one hit another?

A problem very similar to this is how quickly two gasses will mix. Gas particles fly around very quickly air molecules at about 400 meters per second (which is faster then the speed of sound!) and all that stops cigar smoke instantly filling a room is that the gas molecules hit off each other so much they do not just zip across the room. The calculations below are based on an explanation found here. Maxwell and a few other worked out how often particles should collide and called the distance a particle travels without colliding the Mean free path.

Each particle has a volume of 63360 cubic meters. So 25 particles are 1,584,000 cubic meters. Instead of being in a box these submarine particles are in the atlantic with an operating range in depth of 300 meters. So the 'box' these particles are in is of size 30 000 000 000 000 000 cubic meters. Each particle has 12 million cubic kilometers to itself. so in 12 million cubic kilometers of ocean 63360 meters of it are particle. So 1 part in 190 000 000 000 of the available Atlantic is a submarine.

So how many particles per meter is that? 25*63360 submarines in 30 000 000 000 000 000 meters cubed of water.

Whats area is swept out by a particle (submarine) in a given period of time? I figure submarines wander around at 20kph so that's a sweep volume of pi*d*d*x in a distance x. travelling at 20kph that's pi*24.7*24.7*(20kph*1000m*24hr)=919994045 meters swept per day.

Now along this path how long will it on average travel before hitting another particle?

The mean free path formula is

where n is the number of particles per unit volume. And r is 24.7m. So the length you'd expect to travel between collisions is 1/2710* n.

Actually i think I've found a flaw in my reasoning here. I think the correct answer is about once ever 300 years. Which is still a bit too often isn't it? Ill post the calculations later.

## Monday, February 16, 2009

### Nuclear submarine collision what are the chances?

"A Royal Navy nuclear submarine was involved in a collision in the middle of the Atlantic, it was reported.

The crash between HMS Vanguard and French submarine Le Triomphant, which was also carrying nuclear warheads, is believed to have occurred on February 3 or 4, The Sun claimed."

A nuclear submarine seems to be about 140 meters with a radius of 12. So that's a volume of about 63360 cubic meters.

The Atlantic ocean is 354,700,000 cubic kilometers. There are 1 000 000 000 cubic metres is a cubic kilometer. Of course subs can only dive to about 400 metres. So say they stay in the top 300 meters then the volume might be more like 106.4 million km squared * 300 meters=30 million cubic km. More likely they avoid the top 20 meters where ships might hit them, so their range is estimated to be 20-2320 meters deep.

This is assuming a submarine is a cylinder which it isn't.
How many nuclear submarines are there? There seems to be about 50 in the world. Navies will keep their own submarines separate. But that still means there are in the Atlantic maybe 25 submarines that the French or UK subs could run into. This does reduce the number of subs the Russians Or Americans can hit significantly though. They have a top speed of about 40 km per hour. So I assume they are wandering around at 20kph. So assuming all the worlds submarines are in the Atlantic ocean at the same time how often would you expect one to hit another if they were traveling round at random?

## Thursday, February 12, 2009

### facebook relationship forensics

Has anyone noticed the modern skill of divining your friends relationship status based on social networking clues? You feel a bit CSI trawling through tweets to divine if someones missus is just not going to the pub or has been red carded.

This requires powers of divination that would shame an extispicist. It would also shame the animal whose entrails he was reading if it didnt have bigger problems at the time.

Why isn't there a word for thinking today is a different day? If you could go "oh the game is on tonight Ive been daisy all day" rather then having to go into an explanation of how you think its Friday not Thursday etc.

## Wednesday, February 11, 2009

### Mind reading maths horse advances scientific method

Clever Hans was a horse. He was a horse who did maths. People held up a card with a arithmetic puzzle to him and he would clop out the correct answer. Now this is a clever trick but the really odd bit is what happened when a guy called Pfungst figured out how he did it.

Pfungst realised that when the person posing the question did not know the answer the maths horse was suddenly thicker then pig shit. When the questioner expected another clop they leaned slightly forward. When the horse had clopped out the right answer they leaned back in amazement.

From this Pfungst realised that in experiments you give off subtle clues that can be picked up and influence the experiment. This was called the "clever hans effect" and is the reason we carry out experiments where the researcher does not know the "correct" answer. This double blinding was an important advance in the scientific method. The lack of double blind is a mistake a lot of paranormal and alternative health experiments make.

Still though Mind reading maths horse, that is just a random collection of words. What non equine advances to the scientific methods have been made? Was the first journal editor was a wiley aristocratic unidexterous fox? Peer review was originally carried out by psychic chemistry goats?

And while were on weird shit, did you know bees can recognise faces? I would have thought the chief advantage of being a social insect was being immune from embarrassment. Now there going to be all "Oh whats your name, I remember I met you by the gladioli yesterday". Forget shitting sugary water maybe we should use bees as bouncers. Giant swarms of bomber jacketed fuckwits baring entry to the pubs of Dublin.