e=mc2

[Huguenot]

Today's fascinating physics fact...

Nuclear bombs generate their 'blast energy' according to Einstein's equation e=mc2 (energy released = mass x speed of light squared).

So a 20 kiloton bomb (the size they dropped on Nagasaki) lost about 0.8 grams of mass - about the weight of a five pound note.

So as you stroll into the pub tonight, it's worth considering that you're packing the equivalent of 5 or 6 nuclear bombs in your wallet.

Scary eh?

[Chick]

So clever.

[Jeremy]

I assume you arrived at your result by converting the Kiloton "TNT equivalent" to Joules. Sounds about right... according to Wikipedia, a max of 0.03% of the mass of the bomb is converted into "useful" energy. And those early bombs were presumably less efficient than modern ones.

[Huguenot]

Yeah. The really wierd thing is that although the bomb materials lose mass, they don't actually lose any material.

This is because the 'mass' of an object isn't just defined by the particles it's made up of, but by the energy within them.

A good example is water: water is made up of two hydrogen atoms and one oxygen atom. However, water (h2o) actually has lower mass than 2 x hydrogen and 1 x oxygen atoms, even though nothing has disappeared.

As you've probably guessed, this is because they're in a lower 'energy state' - so energy is released when hydrogen and oxygen are combined to create water.

This is how the Space Shuttle main engine works - it combines hydrogen and oxygen releasing the energy. Hence that big plume of 'smoke' out of the back isn't smoke at all - it's water.

In a nuclear bomb the by products of nuclear fission have the same 'particles' that they had before: they just have lower mass.

Freaky.

[mockney piers]

"Wikipedia trivia: if you take any article, click on the first link in the article text not in parentheses or italics, and then repeat, you will eventually end up at "Philosophy""*

Wow, tried it on Blackbird and it worked.

*from xkcd

[Laddy Muck]

Fascinating.

[mockney piers]

...and chewing gum.

[Guest]

Thank goodness - only 5 posts before someone reduced it to a level I can understand. Bless you, Mockney.

[david_carnell]

It took me 18 clicks to get from:

Naftoruon

Naftoruon is a village in the municipality of Osak?cə in the Lankaran Rayon of Azerbaijan - this was a random article selection.

to

Property (Philosophy)In modern philosophy, mathematics, and logic, a property is an attribute of an object

It's like an intelligent variation of Six Degree of Kevin Bacon.

[Guest]

12 clicks from Plum to Property (Philosophy).

Found a new 5-letter word along the way which I'm now longing to work into the 5-letter word thread. Bonus.

[david_carnell]

Do you get points for most or fewest clicks?

[mockney piers]

most, 18 must be pretty good.

Chewing gum was 16, Blackbird 13. Seems we have a target to beat people.

[Loz]

david_carnell Wrote:

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> Do you get points for most or fewest clicks?

Most, obviously. Else I bagsie 'philosophy' - 0 clicks.

[david_carnell]

I got 18 again with Takanobu Otsubo (born 15 June 1976), the Japanese long-distance runner who specializes in the half marathon.

[Loz]

Ironically Kevin Bacon -> Philosophy = 20 clicks, via "mammary glands" and "organ".

And his middle name is 'Norwood'.

[david_carnell]

I trump you with 23 clicks from Archbishop Alter High School, also known as Alter High School, a Catholic high school in Kettering, Ohio, United States.

Via the United States and Taxonomy

[mockney piers]

Battle of the Alamo takes 20.

[mockney piers]

BAh, trumped

[Loz]

DC - what the hell made you try that? Is that your old school?

[Salsaboy]

Handyman - got up to 26 before I realised it had got into a loop and the same pages kept coming up, none of them Philosophy.

I think I beat it.>:D<

[reggie]

I have never thought of chemical reactions such as burning hydrogen as producing changes in mass so thankyou hugs for enlightening me.

Though for the casual observer, producing water from oxygen and hydrogen is not a 'nuclear' reaction in the same vein as an atomic bomb. The changes in energy state are to do with electrons and not part of the nucleus.

Agreed?

[mockney piers]

Nope, handyman was 13. Quickly hit the sciences and then you're doomed.

The rule is first word not in parantheses or italics.

[Jeremy]

reggie - a worthy post I'm sure, but to be blunt, nobody seems interested any more. The Wikipedia Philosophy thing is more fun.

[david_carnell]

Loz Wrote:

-------------------------------------------------------

> DC - what the hell made you try that? Is that

> your old school?

Nah.....just click on the "Random Article" link. Makes life more fun.

[Salsaboy]

mockney piers Wrote:

-------------------------------------------------------

> Nope, handyman was 13. Quickly hit the sciences

> and then you're doomed.

>

> The rule is first word not in parantheses or

> italics.

Oh yeah, just seen where I went wrong. Clicked on 2nd word at one point. Bummer.