"Clive George" wrote in message
o.uk...
"dennis@home" wrote in message
...

No you have not, go on explain it.
Just admit that your claim that all energy storage increases mass is
wrong.
Either that or explain why the hotter water (with the higher relativistic
mass) is at the bottom after releasing energy and how that fits with your
claim.

Do you have any idea at all how little idea you have about what's going on
here?

Hint : Mass != Density. Another hint : The mass changes people are talking
about here are _tiny_.

Did you see me mention volume anywhere?
Why do you want to introduce an irrelevant measure into this?
I said the same water, molecule for molecule.
It goes to show how little you know.

On Tue, 22 Sep 2009 14:26:54 +0100, Paul Martin wrote:

And comedians (who have had to change their names under Equity rules)
and ATV schools programme producers...

But not quite as well known as the former Prime Minister, or perhaps the
New Jersey Devils hockey player

In article , The Natural Philosopher
wrote:
dennis@home wrote:


"The Natural Philosopher" wrote in message
...

Is it so hard to grasp that the water at the bottom is fractionally
lighter because its lost energy, but fractionally slightly less
light because SOME of its potential energy is retained as heat
energy?


Waffle.

So now you are claiming that the potential energy in the water at the
top is in real mass?

No, I am saying that is what Einstein's theories say.

I sometimes wonder if even teaching special relativity to undergrads is a
tactical error. It leads to all kinds of confusion on the part of those
that assume special relativity *is* relativity and there is nothing else to
'relativity'.

Thus allowing people to pop up with all kinds of mistakes like the "twin
paradox" and - in this thread - ideas like "relativitic energy" that...

It can't be in relativistic energy as the water at the top is colder
and hence stuff is moving more slowly.

,,,they assume only arises due to differences in velocity in the
measurement frame.

Maybe the error was using the word 'Special' which might make it seem 'more
important' than mere 'General'. :-) Whereas the 'special' means something
like "Relativity for simplified situations where we ignore many factors
that may turn out to matter in reality".

Alas in my experience General Relativity is often taught by theorists and
mathematicians who use math without bothering much with mere words. Which
is fair enough given that some of the ideas are difficult for some to
grasp. And OK for others who can twig from the maths. But leads to people
not seeing the physics for the maths.

Yes, General Relativity does indeed say that the inertial mass of items
does vary if you move them up or down in a gravitational field. Yes, that
would be for each individual atom, or other particle. But don't take my
word for it. Go read the textbooks on the topic if you doubt this. Then
check out some of the experimental tests that have been done to probe the
relaibility of GR.

That said, I think I do agree that the problem here is probably the density
of trolls rather than the mass of physical objects. :-)

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 2009-09-22, Paul Martin wrote:
In article ,
On Mon, 21 Sep 2009 14:20:53 +0000, Paul Murray wrote:
One often-misinterpreted aspect of the energy-mass unification is that a
system's mass increases as the system approaches the speed of light.
This is not correct.
How does this fit with the relationship

m = m0 / sqrt [ 1 - (v/c)^2 ]

To an outside observer, the mass increases. To the object, in its own
frame of reference, there is no change in mass. In fact, from its point
of view the outside observer has gained mass.

Which makes sense to anyone who has ever attended a school reunion.
Everybody except you always looks much fatter.

On Tue, 22 Sep 2009 15:23:54 +0100, Paul Martin explained:

To an outside observer, the mass increases. To the object, in its own
frame of reference, there is no change in mass.

But an object can only be aware of its mass unless it interacts with
something else.

In fact is it not true to say that an object only has existence because
of its relationship to / interaction with other objects?

Is there any formal relationship to the similar observation:

Returning Astronauts: We have been gone 3 days

Earth Observers: No, you have been gone 3 years

In fact, from its point of view the outside observer has gained mass.

Yes it all depends on the frame of reference.

So since everything is apparently in motion (assuming the universe
is expanding) how can anybody say with certain what the rest mass
of an object is?

Even if the universe is not expanding, measuring the mass of an apparently
"stationary" object is still not going to give it its rest mass since it
is moving relative the the axis of the earth and also relative the the
axis of rotation of the solar system.

So if there was no observer, the mass would not have changed at all?

You are carrying:
tea,
no tea,

Why no coffee?

the thing your aunt gave you which you don't know what it is...

And a cat which may or may not be dead?

On Tue, 22 Sep 2009 15:18:00 +0100, Paul Martin wrote:

That's Entropy, man.

Entropy has a bad tendency to increase.

So if entropy is increasing, does that not mean that there was a
starting point where things were more ordered?

How are more ordered systems put into place?

Do they just occur randomly from big bangs?

In article ,
Paul Martin wrote:

Mass is that measurable quality which a body has which resists its
change in motion under the influence of a force.

That's inertial mass. There's also gravitational mass, which
is what is relevant he

Weight is the force exerted by a mass when prevented from changing its
motion under the influence of gravity.

Inertial and gravitational mass are equal, to the precision of all
experiments done so far, and are both proportional to the amount of
"stuff" in the object plus the binding energy.

-- Richard
--
Please remember to mention me / in tapes you leave behind.

"dennis@home" wrote in message
...


"Clive George" wrote in message
o.uk...
"dennis@home" wrote in message
...

No you have not, go on explain it.
Just admit that your claim that all energy storage increases mass is
wrong.
Either that or explain why the hotter water (with the higher
relativistic mass) is at the bottom after releasing energy and how that
fits with your claim.

Do you have any idea at all how little idea you have about what's going
on here?

Hint : Mass != Density. Another hint : The mass changes people are
talking about here are _tiny_.

Did you see me mention volume anywhere?
Why do you want to introduce an irrelevant measure into this?
I said the same water, molecule for molecule.
It goes to show how little you know.

Ah, ok, you're talking about something different. You're still wrong -
you're saying the water molecules are identical apart from their
temperature, but are avoiding the fact that they're in different places
relative to a rather large mass (earth) therefore there's energy = mass to
take account of there.

Stuart Noble
wibbled on Tuesday 22 September 2009 13:51

J G Miller wrote:
On Mon, 21 Sep 2009 14:20:53 +0000, Paul Murray wrote:

One often-misinterpreted aspect of the energy-mass unification is that a
system's mass increases as the system approaches the speed of light.
This is not correct.

How does this fit with the relationship

m = m0 / sqrt [ 1 - (v/c)^2 ]


So the Cambridge and Imperial College men now seem to be saying that
neither has a clue. Makes the rest of us feel better I suppose.

Seems clear enough to me...

The key is "relative" in "relativity". Every non accelerating frame of
reference thinks the above formula only applied to other people (frames of
reference) where v is the *relative* speed. Within each frame (or system)
things seem unaffected.

The weird bit is that it appears to count both ways - A thinks B got more
massive and B thinks A got more massive. The same formula also gives the
length contraction factor and the time dialation factor (which is you think
about it, there is a good reason why all three are affected by the same
forumla).



--
Tim Watts
The ****artist formerly known as Tim S

Explaining magnetism to little children:
"The magnet has a boy end and and a girl end and a boy and a girl like to
hold hands. Magnets aren't gay so two boys or two girls push each other
away..."

"The Natural Philosopher" wrote in message
...

It isn't. It takes a lot more man hours to manage and keep the bloody
things doing anything useful than it does to mine and refine Uranium.


For both nuclear and wind, with wind being slightly less so, since it has
far higher ongoing costs than nuclear.

TNP, I'd like to read more about this. Do you have any sources that explain
more about why wind power is expensive in terms of money and CO2?

Thanks.

SteveT

"Derek Geldard" wrote in message
news
The whole kit and caboodle of recent house wiring, Ring Main, 13A
mains sockets, 13A fused mains plugs, and appliance leads was
introduced to save copper during the early shortages after the war.

So they say.

What I think is strange is the way nobody seems to have considered the
obvious hidden failure mode (a reliability engineer hates hidden failure
modes). The ring architecture allows current to flow in both directions
around the ring to a given socket, thus reducing the required conductor
gauge and saving copper.

But if you break the ring, all the sockets continue to work, but with only
half the current capacity. And there's no way you'd know that until the
wiring overheats.

If you are about to argue that 2.5mm copper is adequate on it's own to carry
the load without fear of overheating (which it may well be), then there's no
point in having a ring!

Does anyone know the full story behind this? The engineers and scientists
back in the 40s and 50s were brilliant - there's no way they could have
overlooked this hidden failure mode, so there must be more to this than I
understand.

SteveT

On Tue, 22 Sep 2009 19:55:00 +0100, Paul Martin wrote:

and is now defined in terms of a specified number of wavelengths of
light given off in a certain energy level transition.

You would appear to be referring to the 1960 CGPM decision on the
definition of the metre.

QUOTE

The metre is the length equal to 1 650 763,73 wavelengths in vacuum of the
radiation corresponding to the transition between the levels 2p10 and 5d5
of the krypton 86 atom.

UNQUOTE

In 1983 the CGPM changed the definition of the metre as the length of the
path travelled by light in vacuum during a specific fraction of a second.

QUOTE

The metre is the length of the path travelled by light in vacuum during
a time interval of 1/299 792 458 of a second.

UNQUOTE

So the base unit metre is now in fact defined in terms of another base
unit, the second.

The specification of light frequencies to be used for the measturement
was further refined in 1992 and 1997 by increasing the number of
recommended radiations from five to eight and then eight to twelve.

Learn more about SI at http://www.bipm.ORG

On Tue, 22 Sep 2009 18:31:36 +0100, Java Jive wrote:

No, to any observer in the same frame of reference (also moving relative
to the axis of the earth and the axis of its rotation about the CoG of
the solar system, and its rotation about the CoG of the galaxy, etc,
etc) the object is truly stationary, and therefore that observer will
measure its rest mass.

But that is measuring its rest mass in that frame of reference (which
may very well be accelerating).

Would its rest mass be the same or different, if it was done in a truly
static environment in an empty, no effect of gravity from large distant
objects, and non expanding Universe?

On Tue, 22 Sep 2009 21:26:24 +0100, Paul Martin wrote:

I blame the old Penguin dictionary of Science in the shelf over there.
:-P

I would have said that you should be using ISO 31, but a check reveals that
this has now been replaced, for most parts by ISO/IEC 80000.

In article ,
Derek Geldard writes:
On Sun, 20 Sep 2009 17:30:58 +0100, "J. P. Gilliver (John)"
wrote:


As one who grew up (from about age 6, anyway) in Germany, I've always
found BS1363 connectors (the "13A" type), both plug and - especially -
socket, far too big - and having a switch on each socket an unnecessary
further complication. If you really want to "turn off at the socket",
you can take the plug out ...

Other countries use different ways of doing their house wiring ,they
have a different set of advantages and disadvantages, and the standard
of electrical installations varies greatly. I say no more.

The whole kit and caboodle of recent house wiring, Ring Main, 13A
mains sockets, 13A fused mains plugs, and appliance leads was
introduced to save copper during the early shortages after the war.

So they say.

That was one of many aims. It wasn't done just for that purpose.
The whole kit and caboodle of recent house wiring, Ring Main, 13A
mains sockets, 13A fused mains plugs, etc is the most recent design
for appliance supplies in the world which is deployed, and it learnt
lots from the schemes already in use in the UK and elsewhere - it
was about 10 years in design with several manufacturers contributing
competeing designs for the 13A plug/socket. One aspect of the system
design was efficient use of copper wiring, whilst providing for high
current loads at very many points around the home. (It was also
designed to allow conversion from a 15A radial system without having
to replace all the existing cable.)

In earlier times when in me mum's house we were only just getting used
to having one power socket per room a lot of appliances with quite a
high current drain (So called "Electric Fires") were sold without
switches, and switching off by pulling the plug out caused burnt
contacts in the 13A sockets.

The switch originates from DC supplies which were used in some areas
(long before 13A outlets) where you have to switch off before unplugging,
as unplugging alone won't stop DC current flow (you just draw a long arc
out of the socket). However, switches on socket outlets had become the
expected norm. Even though no longer a regulatory requirement, absence
of them was seen as being "cheap", so they are retained solely by
consumer demand.

(Other designs of plug don't lie in wait for your bare feet either ...)

No, they just break instead, which you discover when you are in the
middle of plugging them in next time and suddenly have a hand full of
live metalwork. ;-) 13A plugs should normally survive being stepped
on.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 22/09/09 22:05, Andrew Gabriel wrote:

[snip]

The switch originates from DC supplies which were used in some areas
(long before 13A outlets) where you have to switch off before unplugging,
as unplugging alone won't stop DC current flow (you just draw a long arc
out of the socket). However, switches on socket outlets had become the
expected norm. Even though no longer a regulatory requirement, absence
of them was seen as being "cheap", so they are retained solely by
consumer demand.

(Other designs of plug don't lie in wait for your bare feet either ...)

13A ones most definitely do, see below..!

No, they just break instead, which you discover when you are in the
middle of plugging them in next time and suddenly have a hand full of
live metalwork. ;-) 13A plugs should normally survive being stepped
on.

Have you ever stepped on the pins of a 13A plug with no shoes on..?
Ouch..!!!


Ivor

On Tuesday, September 22nd, 2009 at 23:59:12h +0100, Java Jive wrote:

My point is that in our measuring system quantity of mass is a
fundamental unit, not a derived one.

That should surely be, mass is one of the seven basic quantities

length l m metre
mass m kg kilogramme
time t s second
electric current I A ampere
temperature T K kelvin
luminous intensity Iv cd candela
amount of substance n mol mole

plus two supplementary quantities angle (radian) and solid angle (steradian).

Thus the SI unit of mass, the kilogramme, is an SI base unit, not a
derived one.

Why a base unit is a thousand of something else is an anomaly, and as
a former mathematics teacher used to say, they should have renamed it
the "de Gaulle or something".

Paul Martin wrote:
In article ,
J G Miller wrote:
On Mon, 21 Sep 2009 14:20:53 +0000, Paul Murray wrote:

One often-misinterpreted aspect of the energy-mass unification is that a
system's mass increases as the system approaches the speed of light.
This is not correct.

How does this fit with the relationship

m = m0 / sqrt [ 1 - (v/c)^2 ]

To an outside observer, the mass increases. To the object, in its own
frame of reference, there is no change in mass. In fact, from its point
of view the outside observer has gained mass.

This is a fair summary of Normans problem. He is living 300 years in the
past,backwards, and retreatng up his own arse at a velocity approaching
light speed.

No wonder the world looks so different.

Paul Martin wrote:
In article ,
The Natural Philosopher wrote:
Paul Martin wrote:
In article ,
The Natural Philosopher wrote:

Engineering, Cambridge.
NatSci/CompSci, Cambridge.

Hi. Paul Martin is a common name but...Hmm.

Magd 1987.

Oh good. You weren't the Paukl Martin in Trinity who got so annoyed with
me for playing Jimi Hendrix while he was studying for his finals then,
in 1972..

Steve Thackery wrote:

"The Natural Philosopher" wrote in message
...

It isn't. It takes a lot more man hours to manage and keep the bloody
things doing anything useful than it does to mine and refine Uranium.


For both nuclear and wind, with wind being slightly less so, since it
has far higher ongoing costs than nuclear.

TNP, I'd like to read more about this. Do you have any sources that
explain more about why wind power is expensive in terms of money and CO2?


Only teh famous quote I heards from some Nu Laber Clone, where she said
that kilowatt for kilowatt, 'Windpower generates 70 times as many jobs
as nuclear'.

which implies its a lot more expensive, since in the final
analysis.,what costs money is paying people to build and maintain
windmills. when they could be doing something more productive. Well
under a sane government they could be. This one will merely retrain them
as telephone sanitisation executives.


Just think of all the boats they will need to fix em for a start.


Thanks.

SteveT

Paul Martin wrote:
In article ,
Steve Thackery wrote:

TNP, I'd like to read more about this. Do you have any sources that explain
more about why wind power is expensive in terms of money and CO2?

Wind power is intermittent. You can't call on it when demand needs it.
Wind provides power only when the wind blows, and when the wind is too
strong the windmill has to protect itself, which involves turning the
vanes to reduce the cross-sectional area facing the wind (ie. little or
no power extracted).

The coldest periods of UK winter weather tend to be when we have a
static high pressure system, with little wind.

Although to be fair, my personal experience is that the worst case heat
loss here, is when its cold AND the wind blows. shiver

On Thu, 17 Sep 2009 10:52:07 +0100, Java Jive
wrote:

On Thu, 17 Sep 2009 00:35:47 +0100 (BST), "Dave Liquorice"
wrote:

1GW, enough for two big cities it says and it will have been doing it
for 39 years when it finally closes.

But how much energy did it take to build it? How much to mine the
ore, refine it (these in another country, so it doesn't appear in our
carbon account), ship it to the UK, maybe process it some more, 'burn'
it, make the waste safe for transport, transport it, process it, and
store it INDEFINITELY into the future,

Not true, in fact. All radioactive isotopes decay according to their
half lives. When they're gone, they're gone.

This cannot be said for some of the very unpleasant carcinogenic and
teratogenic not to say just plain poisonous chemicals in toxic wastes.

for we will be expending energy
looking after and containing nuclear waste long after the sites that
produced it have been decommissioned. How much energy will it take
entirely to decommission the plant safely at the end of its working
life? By the time you've added up that lot, just how much 'net'
energy will the plant have produced?

More than enough to make all the greeny's **** boil.

If any? A recent BBC programmes about Windscale/Sellafield cast doubt
on how much energy it ever produced. After all, it was primarily
built as a source of weapons-grade plutonium, not to supply
electricity, which was just a public cover story, and the programme
stated that it was sometimes drawing power from the grid rather than
supplying power to it!


It'as true, it was a weapons plant.

However nobody's talking about building any more crypto weapons
plants.

A recent BBC programme about Dounreay revealed that its
decommissioning employs as many people as it ever did when it was
operational. This inevitably means that it will produce incidental
CO2 until decommissioning ends in 2025, even though it hasn't been
operational since 1994.


AFAIK nobody's proposing the building of any more experimental fast
breeder reactors, looks like it was an expensive experiment in the
1950's.

And that's not even to mention environmental radio-active hazards ...


Go on , I challenge you. Mention them.

A school-friend's family had to pour all their milk into the sea
during the incident at the then Windscale plant.


That was not the case. The milk could have been made into cheese and
stored until the I 131 had decayed away. Result = normal cheese.

http://en.wikipedia.org/wiki/Windscale_fire

There are Welsh farmers still unable to sell their lamb after
Chernobyl:


It's not the lamb that's the problem it's the ceasium source. ;-))

http://www.walesonline.co.uk/news/wa...1466-20822842/


We don't propose to do what the Soviet russians did in Chernobyl.

The same BBC programme revealed (newly to me, at least) that there are
heavy particles washing along the coast from Dounreay:

http://www.iop.org/EJ/article/0952-4...b-754751b7c89c


And this is a problem how? Do you think the BBC know better than the
NRPB ?

And, don't forget, every spillage, leak, incident, or whatever,
whether it be major like Chernobyl and Three Mile Island, or the more
frequent lesser problems,


Like disposing of used latex gloves, syringes, and needles as low
level waste?

besides the instantly alarming concerns
about radio-activity, have an associated energetic cost in cleanup
operations, etc.


Perhaps you could list the costs borne in the UK by the production of
electrical energy alone, in cleaning up nuclear catastrophies.

AFAIAA not one single person has died in the UK from a civil nuclear
accident. - in all time - period.

The really big windmills are 2MW so you need 1500 "jumbo jets on a
stick" spread out over the country to have even a hope in hell of
matching this one nuke station.

It is certainly true that wind has its own problems, the chief of
which are that most of the population do not choose to live where most
of the wind is, the number of windfarms that are required to be built
in an impossibly short time, and the only commercial manufacturer in
the UK has just closed.

First they should make it work, then they can talk about it.

However, planning permission aside, a
windfarm has a much smaller lead time,

But they don't work !

and a much smaller initial CO2 outlay to recover.

So all these become secondary issues.

We need to use as much wind as we can, but it
clearly won't be sufficient on its own.


Glad you agree. It doesn't work.

Derek

On Sun, 20 Sep 2009 17:42:09 +0100, "J. P. Gilliver (John)"
wrote:

In message , Timothy Murphy
writes:
PeterC wrote:

My TV is 0.9W; the digibox is 9W (with a PF of 0.45!) so
well worth switching off.

Perhaps manufacturers should be required to specify
standy power consumption.
I've been surprised how much difference I have found
eg between different computer monitors.

One of the high-street chains I looked in somewhere in the last few
months - I think it was Currys or Currys Digital (i. e. the old Dixons),
or Comet - _did_ have on and standby consumption figures on the
shelf-edge tickets, at least for freeview boxes which is what I was
looking at at the time.

I'd also like CFL manufacturers to be required
to specify the illumination in lumens.


Hear hear - though make that for all light sources, i. e. filament bulbs
too.

The figures for standard wattage GLS lamps are readily available.
CFL's not (they are all different).


What _I_'d like them (or the distribution chain, i. e. supermarkets
etc.) to be obliged to do is offer some higher-power ones: say 30 or
35W. The availability of these would IMO counter a lot of the resistance
among the public to them. At present, the highest widely-available is
the type that at best match a 100W filament bulb once they've come up to
full strength, thus in the mind of most people they're "not as bright".

No they say protest because the public have been cynically lied to
about the output of CFLs which has been "kited" in an unbelieveable
way.


(Another option would be to make a combined bulb, which turned on a
filament initially, backing it off as the CF [what's the L for?] one
comes up, either via a light sensor, or just a timer.)

That makes as much sense as a combined refrigerator / lawn mower.

(Finally - for now! - why _do_ they come up so slowly, when ye olde
fluorescent striplights, apart from while they're actually striking,
come on with more or less full brightness from the start?)

The green ****pots have reduced the Mercury content to what is *the*
*bare* *minimum* light output does not reach normal levels 'till all
the mercury has evaporated in the bulb.

Derek

In article , J G Miller
wrote:
On Tue, 22 Sep 2009 18:31:36 +0100, Java Jive wrote:

No, to any observer in the same frame of reference (also moving
relative to the axis of the earth and the axis of its rotation about
the CoG of the solar system, and its rotation about the CoG of the
galaxy, etc, etc) the object is truly stationary, and therefore that
observer will measure its rest mass.

But that is measuring its rest mass in that frame of reference (which
may very well be accelerating).

The difficulty here is using the term 'rest', for you reason you allude to.
This term makes sense in special relativity, but becomes ambiguous in GR.

if you stand and hold a mass whilst standing on the Earth, then both it and
you *are* accellerating according to GR. if the mass is then lifted and
held above you so that its distance from you seems not to change, then both
it and you are still accellerating. But now by different amounts. You don't
'see' the acceleration but that is the GR view of the situation.

The point here is that if you and the mass were in the equivalent of a
'rest' frame you would experience no forces. i.e. you'd both have to be in
free fall under any gravity. But if something is holding you at a set
distance from the earth, you aren't in a 'rest' frame because of the
gravity. It leads to various effects which have been measured and confirmed
to agree with GR. So if people don't understand this or don't want to
accept it, then it is open to them to read the experimental reports in the
relevant journals and then say what the errors were in all the
measurements, etc.


Would its rest mass be the same or different, if it was done in a truly
static environment in an empty, no effect of gravity from large distant
objects, and non expanding Universe?

You'll be asking about Mach next. :-)

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On Wed, 23 Sep 2009 03:12:56 +0100, Derek Geldard wrote:

I'd also like CFL manufacturers to be required to specify the
illumination in lumens.

Hear hear - though make that for all light sources, i. e. filament

bulbs too.

The figures for standard wattage GLS lamps are readily available.
CFL's not (they are all different).

All the bulbs, any type, that I've looked at on the shelves recently
have the lumens output on the packaging or the bulb itself. It's
never in the marketing hype labeling but tucked away somewhere in
small type. Sometimes on one of the flaps on the bottom of the box.

No they say protest because the public have been cynically lied to
about the output of CFLs

Agreed but at least these days with the lumen output available on the
packaging those with half a brain cell can see the truth.

--
Cheers
Dave.

On Wed, 23 Sep 2009 03:03:15 +0100, Derek Geldard wrote:

Not true, in fact. All radioactive isotopes decay according to their
half lives. When they're gone, they're gone.

"Half life", the period of time it takes for half of the orginal
substance to have decayed. After that time it's another equal period
for the next half to decay, still leaving you with 1/4 of the orginal
amount.

Of course it depends on the substance how long the half life is, they
vary from seconds to thousands of years but most are fairly short and
the level of radiation decreases over time as well. The nature of the
radiation is important as well, alpha particles are easyly stopped
for example.

This cannot be said for some of the very unpleasant carcinogenic and
teratogenic not to say just plain poisonous chemicals in toxic wastes.

Aye, that just sit more or less for ever.
AFAIAA not one single person has died in the UK from a civil nuclear
accident. - in all time - period.

And plenty have been killed in the production of coal, oil and gas.

--
Cheers
Dave.

On Sep 23, 10:02*am, "Dave Liquorice"
wrote:
On Wed, 23 Sep 2009 03:03:15 +0100, Derek Geldard wrote:
Not true, in fact. All radioactive isotopes decay according to their
half lives. When they're gone, they're gone.

"Half life", the period of time it takes for half of the orginal
substance to have decayed. After that time it's another equal period
for the next half to decay, still leaving you with 1/4 of the orginal
amount.

Of course it depends on the substance how long the half life is, they
vary from seconds to thousands of years but most are fairly short and
the level of radiation decreases over time as well. The nature of the
radiation is important as well, alpha particles are easyly stopped
for example.

This cannot be said for some of the very unpleasant carcinogenic and
teratogenic not to say just plain poisonous chemicals in toxic wastes.

Aye, that just sit more or less for ever.

AFAIAA not one single person has died in the UK from a civil nuclear
accident. - in all time - period.

And plenty have been killed in the production of coal

And condemned to a slow death through lung disease that is probably
just as distressing to them and their families as if they were dying
of radiation poisoning.

MBQ

On Sep 23, 10:16*am, Java Jive wrote:

In the quote on Dounreay below, it states that it will become a
brownfield site by 2336,

Absolutely irrelevant in the context of modern civil nuclear plant.

I don't supposee the Soviets planned to do what we did at Windscale

Absolutely irrelevant in the context of modern civil nuclear plant.

A lot of people were killed and seriously injured in the early days of
steam power, due to bioler explosions. Countless thousands have been
KSI by motor vehicles. In just the same way that these cases didn't
stifle the development of the technology, you can't use Windscale,
Dounreay or Chernobyl as arguments against the development of civil
nuclear power.

So we're left with one isolated incident at Three Mile Island.

MBQ

On Wed, 23 Sep 2009 09:54:00 +0100 (BST), "Dave Liquorice"
wrote:

All the bulbs, any type, that I've looked at on the shelves recently
have the lumens output on the packaging or the bulb itself. It's
never in the marketing hype labeling but tucked away somewhere in
small type. Sometimes on one of the flaps on the bottom of the box.

Yup. Just picked up two and the info is right there on the top of the
box.

Osram 15w (75w equiv) - 900 lumens
Philips 20w (100w equiv) - 1200 lumens

Now, yes, doubtless someone will come along and start screaming that
1200 lumens is not "equivalent" to a 100 watt bulb at all, and that
it's all a brainwashing conspiracy by "The Greenies". That aside, if
it means I use a "60w equivalent" CFL instead of a 40 watt bulb,
that's fine. The CFL still lasts longer, uses one quarter of the
electricity of the bulb, and doesn't waste my money heating the
spiders on my ceiling.

--

On Sep 23, 12:04*pm, (Zero Tolerance)
wrote:
On Wed, 23 Sep 2009 09:54:00 +0100 (BST), "Dave Liquorice"

wrote:
All the bulbs, any type, that I've looked at on the shelves recently
have the lumens output on the packaging or the bulb itself. It's
never in the marketing hype labeling but tucked away somewhere in
small type. Sometimes on one of the flaps on the bottom of the box.

Yup. Just picked up two and the info is right there on the top of the
box.

Osram 15w (75w equiv) - 900 lumens
Philips 20w (100w equiv) - 1200 lumens

Now, yes, doubtless someone will come along and start screaming that
1200 lumens is not "equivalent" to a 100 watt bulb at all, and that
it's all a brainwashing conspiracy by "The Greenies". That aside, if
it means I use a "60w equivalent" CFL instead of a 40 watt bulb,
that's fine. The CFL still lasts longer, uses one quarter of the
electricity of the bulb, and doesn't waste my money heating the
spiders on my ceiling.

And looks pig ugly in alot of light fittings!

MBQ

"Man at B&Q" wrote in message
...
On Sep 23, 10:02 am, "Dave Liquorice"
wrote:

And condemned to a slow death through lung disease that is probably
just as distressing to them and their families as if they were dying
of radiation poisoning.

When I was in my aerial-rigging prime I did a lot of work on the estates
built by the mine owners and later the NCB. It sometimes seemed as if every
second house had a poorly bloke in bed in the front room, his lungs full of
****e. The NHS used to send a lorry round dropping oxygen bottles off.

Bill

On Sep 23, 12:20*pm, Java Jive wrote:
On Wed, 23 Sep 2009 02:28:52 -0700 (PDT), "Man at B&Q"

wrote:

On Sep 23, 10:16*am, Java Jive wrote:

In the quote on Dounreay below, it states that it will become a
brownfield site by 2336,

Absolutely irrelevant in the context of modern civil nuclear plant.

How so? *Has someone known only to you invented a new type of nuclear
power plant that doesn't use radioactive substances and therefore
doesn't require decommissioning and making safe?

Don't be silly.

Irrelevant because Dounreay was an *experimental* fast breeder
reactor. They don't make build them anymore and any comparison with
them is irrelevant.


I don't supposee the Soviets planned to do what we did at Windscale

Absolutely irrelevant in the context of modern civil nuclear plant.

It is absolutely relevant because it was run by the same error-prone
species of human beings as would be running any new ones.

It was being run by error prone night shift. I doubt any western
nuclear operator would perform experiments like that on a live
reactor.

MBQ

On Sep 23, 10:16*am, Java Jive wrote:

Perhaps you could list the costs borne in the UK by the production of
electrical energy alone, in cleaning up nuclear catastrophies.
AFAIAA not one single person has died in the UK from a civil nuclear
accident. - in all time - period.

I don't have costs or deaths for the UK alone, but there is a world
list of incidents with some immediate mortality figures he

http://en.wikipedia.org/wiki/List_of...lear_accidents

How many fatalities?

How many died in a single incident on Piper Alpha?

Do we stop all oil and gas drilling because it's too dangerous, let
alone the polution and supposed climate damage resulting from burning
it.

Nuclear power doesn't even register if you want to talk about
fatalities. If you include seriously injured it still comes nowhere.

MBQ

In article ,
Java Jive wrote:

You clearly have no understanding of the definition and meaning of
half-life. The half-life is the amount of time that it takes for half
a given amount of radio-active substance to decay. What about the
other half? That takes half again, etc. So you end up with ...

1 1/2 1/4 1/8 etc

... of the original amount. A substance with half-life decay is thus
never truly 'gone', the best one can hope for is that danger from it
becomes less than danger from background radiation.

If you're going to be pedantic, eventually your calculation will
result in less than one atom left, so sooner or later every atom will
have decayed. A mole of atoms - say 3 grams of tritium - has 6x10^23
or about 2^80 atoms, so after about 80 half lives - about a thousand
years in the tritium case - there will really be none left.

Of course, in practice, many dangerous radioactive substances have
sufficiently long half-lives that they will continue to be a danger for
far longer than we can foresee the future.

-- Richard
--
Please remember to mention me / in tapes you leave behind.

In article ,
Paul Martin wrote:

0.6nkg = 600ng, which is definitely measurable. You can't use SI units
like that.

I don't see why not:
[...]

http://physics.nist.gov/cuu/pdf/sp811.pdf

If by "can't" you mean "are advised not to by various standards",
then yes. But I took it as "it doesn't make sense to", which is
false.

-- Richard
--
Please remember to mention me / in tapes you leave behind.

In article , Richard Tobin
wrote:

Of course, in practice, many dangerous radioactive substances have
sufficiently long half-lives that they will continue to be a danger for
far longer than we can foresee the future.

The problem with the above is that it combines two conflcting factors in a
way that make the claim for "danger" ambiguous or misleading.

The longer the half-life, the smaller the percentage of the atoms that tend
to decay per unit time. Thus the level of 'radiation' tends to reduce for a
given amount of material if the half-life is longer.

Hence materials which have very long half-lives have - in terms of activity
(numbers of decays per second per unit mass) - that are lower than
materials with very short lives. i.e. not as radioactive.

So a very long half life can be a sign of *less* 'danger'. The situation
isn't as simple as the above assertion.

Thus there is an inherent problem with those who worry about radiation
describing *both* long half lives *and* high levels of activity as
'dangerous' without understanding the distinctions. Apples and Oranges.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On Wed, 23 Sep 2009 14:44:06 +0000, Richard Tobin wrote:

If by "can't" you mean "are advised not to by various standards",
then yes.

If you are using SI units, then you are *forbidden* from doing so.

From http://www.bipm.ORG/en/si/si_brochure/chapter3/prefixes.html

QUOTE

Compound prefix symbols, that is, prefix symbols formed by the
juxtaposition of two or more prefix symbols, are not permitted.

This rule also applies to compound prefix names.

UNQUOTE

On Wed, 23 Sep 2009 14:40:29 +0000, Richard Tobin wrote:

so sooner or later every atom will have
decayed.

Unless you have a cat.

BW

On Sep 16, 4:47*pm, "Steve Thackery" wrote:
JJ, I think we are in what is known as "violent agreement" here! *At least,
pretty close to it.

SteveT

All this this because electricity means burning coal or gas?????

I was filling in one of those 'What is your carbon foot print'?
questionnaires; from the UK, from here in eastern Canada.

One question was how much electricity do you use? Then realizing that
now in the high 90s% percent of ours is hydro generated and that
percentage will increase to close to 100 when the Lower Churchill in
Labrador is connected to the rest of this province some years from
now.

Hmm! that's misleading question even where we, during a much longer,
colder and tougher winter use more energy for heating etc. Here (this
part of Canada) btw air conditioning is virtually unecessary' except
where maybe a heat pump can be reversed to provide it. Unlike the
central parts of the North American continent!

Then realized that there was no provision in the questionnaire, along
with how many miles/kilometres do you drive, for any other alleviating/
offsetting activities

So went out and counted the number trees we have planted since we
built this house in 1970. I was up to 67 when I was interrupted. So
somewhere around 70 trees on this approx half acre which contains our
1970 house plus daughter's approx 18 year old one.

Mixture of dogberry (mountain ash) maples, a few oaks, quite a lot of
beech (not native here AFIK but grows well and withstands ice build-
ups) local birch and evergreen spruce/fir etc. Every year now for many
years birds have been nesting in these trees that we planted ourselves
from seedlings, acorns and conkers etc. Some trees over 30 feet high,
despite short/slow growing seasons. Had to remove two big ones because
they threatened to fall on the house! Each was over a foot around at
the base (How to get rid of the stumps?).

So; a question. Rather than fiddling around with CFLs
etc. .............. How many trees or other oxygen producing and
carbon containing plants/trees/bushes have 'you' planted. Don't count
grass it's not very good at returning nutrients to the soil anyway.
Clover is better and is more insect resistant.

Cheers.

Java Jive wrote:
On 23 Sep 2009 14:40:29 GMT, (Richard Tobin)
wrote:
If you're going to be pedantic, eventually your calculation will
result in less than one atom left, so sooner or later every atom will
have decayed. A mole of atoms - say 3 grams of tritium - has 6x10^23
or about 2^80 atoms, so after about 80 half lives - about a thousand
years in the tritium case - there will really be none left.

True enough. 9/10 sir?

Of course, in practice, many dangerous radioactive substances have
sufficiently long half-lives that they will continue to be a danger for
far longer than we can foresee the future.

Which of course is the real point ...

And of course, if there weren't such elements *already present in the
earths crust*, we wouldn't be able to use nuclear power.

Which is, of course, the real point..

In essence, all we are doing is scarping dangerous stuff out of the
ground, concentrating it, and bringing it under human control, rather
than leaving it lying around the place.