Jump to content

e=mc2


Huguenot

Recommended Posts

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?

Link to comment
Share on other sites

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.
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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?

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Latest Discussions

    • They have. They asked in the original consultation. I’ve talked about it above. Around 3000 people (57% of a self selecting sample), were against the scheme. But the point you seem to be struggling with is that it wasn’t a referendum. We don't routinely have referenda on matters public policy in the UK (Brexit aside). We elect people to make decisions and then we judge the quality of those decisions in the round, and either re-elect them, or kick them out. That’s representative democracy. It’s not a good idea imo, but happy to listen if you do want to make the case for the routine use of referenda in matters of public policy. Not so much if you just want to use it selectively for a single issue you feel strongly about. Still ducking the question I’ve posed to you more than once now on claim of inadequate signage and intimidation of emergency services I note. I actually think the majority quietly support the local LTN. Certainly polling across London shows most Londoners support them generally. The local elections also suggest that most people either support it, or don’t feel strongly enough either way for it to stop them re-electing those who oversaw the implementation. I don’t believe in routinely holding referenda on matters of public policy. There are many reasons for this but  I don’t want to steer the thread off topic. Hopefully any sensible person reflecting on it for a second will understand the reasons why it wouldn’t be desirable. Still waiting for someone to defend One Dulwich’s claims as laid out above.
    • Sounds like you are running scared of the idea Earl, come now with so much debate over what is a consultation /referendum surly it's a simplel way of settling the argument 🤔 
    • Pot holes feel like they’re becoming more of an issue (based purely on my perception, don’t know what data there is). Even worse outside London imo. I suspect as Mal says, heavier vehicles are part of the problem (both SUVs, but also EVs which are generally heavier than ‘conventional’ cars), but regardless the council need to be more on it.  You can use the fixmystreet app to report them (and other street maintenance issues). 
    • Prior to the LTNs do you have many examples where the results of consultations were not acted upon? Seems to me the council is picking and choosing when they action the feedback from their constituents.......   Have you looked at the results from that, if not, tale some time to have a look, its quite enlightening..it seems the majority do not think the changes will have the desired effect....but you know it's not a refendum so the council has chosen to ignore the feedback of constituents. They must be assuming full responsibility for ignoring residents feedback- clearly they think they know what's best for us. If it all goes wrong let's see if they take responsibility!   Earl, here's a question for you (and i know you wont answer it but lets see)...why do you think the council has never asked a yes/no question to local residents about anything to do with the LTNs - wether they exist or whether we think the changes they have suggested (using our money) are needed/worthwhile? Or a consultation with a yes/no answer but we all know why. I still laugh that the council had to re-run the CPZ consultation with a yes/no answer and finally had to listen to their constituents...they took a hell of a spanking! They have been cheating the system for years and getting away with it. So does that not apply during consultations then? (P.S before you answer take a look at the definition of a consultation as provided by the Local Government Association).
Home
Events
Sign In

Sign In



Or sign in with one of these services

Search
×
    Search In
×
×
  • Create New...