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Author Topic:   Misconceptions of E=MC^2
kongstad
Member (Idle past 2870 days)
Posts: 175
From: Copenhagen, Denmark
Joined: 02-24-2004


Message 121 of 243 (452701)
01-31-2008 3:06 AM
Reply to: Message 111 by pelican
01-30-2008 8:05 PM


Re: E=MC2 experiments explained in simplest forms
The most simple example I can think of is this.
In the atom, there is a nucleus and electrons. The electrons can be excited, which means they can be in higher states of energy.
They will however "try" to go back to lower states. To do this they must lose som energy. They do this by emitting a photon. A photon has mass (not rest mass though), so this is an example of energy being converted to mass.
You see it happen all the time, since this is the basis for microwave ovens and laser, such as those in your DVD drive.
You can see an animation of this here grossly simplified though:
http://www.upscale.utoronto.ca/...Model/Flash/BohrModel.html
What happens in the animation is that a photon is absorbed by the electron. The photon has mass, since it has energy. When it is absorbed it excites the electron, transferring all of the energy to the electron, and the photon ceases to exist. The electron later emits a new photon with mass equivalent to the energy.

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Kapyong
Member (Idle past 3442 days)
Posts: 344
Joined: 05-22-2003


Message 122 of 243 (452716)
01-31-2008 6:49 AM
Reply to: Message 69 by pelican
01-30-2008 12:21 AM


Re: E=MC2 experiments
Hiya,
quote:
...experiments with e=mc2
Haven't you noticed yet that you keep writing the formula wrong?
e=mc2 is wrong.
The correct formula is e=mc^2.
And,
it DOES NOT mean moving mass at the speed of light squared.
It doesn't mean that.
But sadly, you don't seem to get it.
Iasion

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New Cat's Eye
Inactive Member


Message 123 of 243 (452795)
01-31-2008 10:48 AM
Reply to: Message 111 by pelican
01-30-2008 8:05 PM


Re: E=MC2 experiments explained in simplest forms
Can you give an example of energy to mass?
cavediver already did in Message 80 where he linked to this page.
Yes I did check them out. I see my mistake.
I should have said, "can you give me a SIMPLE example that the layman such as myself can comprehend?"
But back in Message 69 you said:
quote:
As it stands e = mc2 i.e the theory of producing matter from energy using the square of the speed of light has never been proved, only the reverse.
The "proof" of that theory exists, it is just not going to be simple. This is one of those cases where you're going to have to trust the experts.
I need a simplified version which I believe you are perfectly capable of doing but don't try.
I'm sorry, but I am not perfectly capable of doing a simplified version.

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Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 124 of 243 (452811)
01-31-2008 11:16 AM
Reply to: Message 122 by Kapyong
01-31-2008 6:49 AM


Re: E=MC2 experiments
Iasion writes:
Haven't you noticed yet that you keep writing the formula wrong?
e=mc2 is wrong.
The correct formula is e=mc^2.
In the interests of completeness, the formula can be expressed typographically in three ways that I know of:
  • E = mc2
  • E = mc^2
  • E = mc**2
As you noted, E = mc2 is incorrect since it says that energy equals mass times the speed of light times 2, but most people have gotten in the habit of ignoring the mistake because they know what is meant and realize that the mistake is due to what happens when you cut-n-paste "E = mc2", since the fact that the 2 is a superscript doesn't copy.
I'm sure you know all this, this is just for the benefit of Heinrik.
--Percy

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NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 125 of 243 (452821)
01-31-2008 11:39 AM
Reply to: Message 111 by pelican
01-30-2008 8:05 PM


Re: E=MC2 experiments explained in simplest forms
I need a simplified version which I believe you are perfectly capable of doing but don't try. I have no evidence to prove this. It is purely my observation.
You have been given enormously simple versions and explanations. If you doubt that ask for the real thing from cavediver. Then you will see the difference.

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johnfolton 
Suspended Member (Idle past 5591 days)
Posts: 2024
Joined: 12-04-2005


Message 126 of 243 (452908)
01-31-2008 6:36 PM


Energy =mass * speed of light squared ?
energy = mass * speed of light squared?
It just seems like an incredible amount of energy in one atom like a mini black hole.
energy/speed of light squared = mass?
It sounds like this would support string theory like energy divided by speed of light squared would equal a mass almost infinititly small in comparision to the size of the atom?
speed of light squared = mass / energy?
speed of light * speed of light = mass / energy?
speed of light = energy / mass / speed of light?
c = square root of energy divided by square root of mass ?
-----------------------------------------------------------------
c=e/m/c solve for c ?
http://www.hostsrv.com/...app1/MSP/quickmath/02/pageGenerate
-----------------------------------------------------------------
Now I'm not sure what I'm saying but what I think I'm questioning is if the square root of energy divided by square root of mass it seems the speed of light squared appears to cancel out? Meaning energy divided by matter going the speed of light time cancels out or that time is dependent on how lights speed is factored. Is this why its believed were seeing the past from the present in that time cancels out when energy divided by mass approaches the speed limit of light?
P.S. It just seems that by moving the forumla the speed of mass can be increased if its converted to energy. However when energy/mass approaches the speed of light it cancels out. Like time for the particle of light going at light speed time stands still because mass/energy is moving at the speed of light?
Edited by johnfolton, : No reason given.
Edited by johnfolton, : No reason given.
Edited by johnfolton, : No reason given.
Edited by johnfolton, : No reason given.
Edited by johnfolton, : No reason given.

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RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 127 of 243 (452925)
01-31-2008 7:33 PM
Reply to: Message 124 by Percy
01-31-2008 11:16 AM


Re: E=MC2 experiments
or
  • E = mcc
    As you noted, E = mc2 is incorrect since it says that energy equals mass times the speed of light times 2, but most people have gotten in the habit of ignoring the mistake because they know what is meant and realize that the mistake is due to what happens when you cut-n-paste "E = mc2", since the fact that the 2 is a superscript doesn't copy.
    One reason to use E = m•c^2


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  • This message is a reply to:
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    Modulous
    Member
    Posts: 7801
    From: Manchester, UK
    Joined: 05-01-2005


    Message 128 of 243 (452936)
    01-31-2008 8:18 PM
    Reply to: Message 126 by johnfolton
    01-31-2008 6:36 PM


    Re: Energy =mass * speed of light squared ?
    It just seems like an incredible amount of energy in one atom like a mini black hole.
    It is an incredible amount of energy. And we've measured it, and confirmed that it is an incredible amount of energy. It is nothing like a mini black hole. In order for it to be a mini black hole it would have to have a much higher density than your average run of the mill day to day atom.
    It sounds like this would support string theory like energy divided by speed of light squared would equal a mass almost infinititly small in comparision to the size of the atom?
    The mass of an atom is not anywhere 'near' infinitely small. It is very small, though.
    .
    Meaning energy divided by matter going the speed of light time cancels out or that time is dependent on how lights speed is factored.
    The velocity of the mass is not part of the equation (see my first post for a more accurate statement).
    Is this why its believed were seeing the past from the present in that time cancels out when energy divided by mass approaches the speed limit of light?
    We are seeing into the past when we look at very distant objects since it takes time the light to get to us. That's all. Not really relevant to the equation at hand other than the idea that c is a constant and finite.
    It just seems that by moving the forumla the speed of mass can be increased if its converted to energy.
    The speed of the mass isn't in there. If you do put it in there, increasing the speed of the mass increases its energy and thus its mass. Reading all this stuff into it is leading you down crazy paths of thinking. It simply says that a thing's energy and a thing's mass are proportional to one another. Increase the energy and you increase its mass. Increase the mass and you increase its energy. In a nutshell, that's all it says.
    When you get that idea, you can consider plugging in the masses velocity. You will find that as it approaches the speed of light the mass (and energy) approaches an infinite value and the amount of work needed to increase the velocity further also approaches infinite. Thus you cannot make a mass travel at the speed of light since it requires infinite amount of work to be done (at least in the UK, you just can't get the staff).
    Edited by Modulous, : No reason given.

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    Coragyps
    Member (Idle past 734 days)
    Posts: 5553
    From: Snyder, Texas, USA
    Joined: 11-12-2002


    Message 129 of 243 (452938)
    01-31-2008 8:31 PM
    Reply to: Message 126 by johnfolton
    01-31-2008 6:36 PM


    Re: Energy =mass * speed of light squared ?
    It just seems like an incredible amount of energy in one atom
    Incredible? Yup. The bombs that destroyed Hiroshima and Nagasaki used up about a gram of matter each to do so.

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    Minnemooseus
    Member
    Posts: 3941
    From: Duluth, Minnesota, U.S. (West end of Lake Superior)
    Joined: 11-11-2001
    Member Rating: 10.0


    Message 130 of 243 (453013)
    02-01-2008 4:36 AM
    Reply to: Message 129 by Coragyps
    01-31-2008 8:31 PM


    0.6 grams of mass lost at Hiroshima
    The bombs that destroyed Hiroshima and Nagasaki used up about a gram of matter each to do so.
    The Hiroshima bomb -
    Little Boy - Wikipedia:
    quote:
    The Mk I "Little Boy" was 10 feet (3 m) in length, 28 inches (71 cm) in diameter and weighed 8,900 lb (4000 kg). The design used the gun method to explosively force a hollow sub-critical mass of uranium-235 and a solid target spike together into a super-critical mass, initiating a nuclear chain reaction. This was accomplished by shooting one piece of the uranium onto the other by means of chemical explosives. It contained 64 kg of uranium, of which 0.7 kg underwent nuclear fission, and of this mass only 0.6 g became energy.
    The Nagasaki bomb used Plutonium. Wiki didn't have mass conversion information as for the Little Boy.
    Fat Man - Wikipedia
    Moose
    Edited by Minnemooseus, : Changed subtitle.

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    bluescat48
    Member (Idle past 4189 days)
    Posts: 2347
    From: United States
    Joined: 10-06-2007


    Message 131 of 243 (453022)
    02-01-2008 8:03 AM
    Reply to: Message 130 by Minnemooseus
    02-01-2008 4:36 AM


    Re: 0.6 grams of mass lost at Hiroshima
    It contained 64 kg of uranium, of which 0.7 kg underwent nuclear fission, and of this mass only 0.6 g became energy.
    that translates to 5.4x1013 Joules (1 Joule equals 1kilogram meter2 second-2

    There is no better love between 2 people than mutual respect for each other

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    Trixie
    Member (Idle past 3706 days)
    Posts: 1011
    From: Edinburgh
    Joined: 01-03-2004


    Message 132 of 243 (453029)
    02-01-2008 8:59 AM
    Reply to: Message 131 by bluescat48
    02-01-2008 8:03 AM


    Re: 0.6 grams of mass lost at Hiroshima
    Just for the sake of clarity, can you post the equation then underneath post it again, but with the terms replaced with moose's numbers? This might help Heinrik.
    Also, given what Fat Boy did, it might be useful to tranlate the 5.4x1013 Joules into what that would do. I know we saw what it does at Hiroshima but using that may be considered cicular, so do you have a wee table that could be posted here showing varying amounts and what they can do? I think his might help to illustrate the point.
    For what it's worth I'm a molecular biologist so my understanding of anything to do with physics is abysmal. I always think of E=mc2 as
    "I have a lump of uranium in my hand. I wonder what the maximum amount of energy that could be released from it is? Hmm.....the amount of energy that could be released depends on how much uranium I have in the first place (ie mass, represented in the equation by "m"). If I plug that mass into the equation where "m" lives, I'll get my answer"
    I know this is simplistic in the extreme, but I wonder if this helps at all?
    Edited by Trixie, : Fat Boy? Fat Boy? Fat fingers more like!!!LOL

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    cavediver
    Member (Idle past 3643 days)
    Posts: 4129
    From: UK
    Joined: 06-16-2005


    Message 133 of 243 (453033)
    02-01-2008 9:14 AM
    Reply to: Message 130 by Minnemooseus
    02-01-2008 4:36 AM


    Re: 0.6 grams of mass lost at Hiroshima
    What you have to remember is that there is nothing special about nuclear reactions creating 'mass loss'. Chemical reactions do exactly the same. If we say Little Boy was 15kilotons, then a conventional explosion of 15,000 tons of TNT will also create a mass loss of around 0.6g.
    In both nuclear explosions and chemical explosuions, the energy released comes from the binding energy - binding energy of the nucleus and binding energy of the atoms/molecules. This binding energy has an assocaited mass via E=mc^2, and it is the loss of this energy that gives rise to the 'mass loss'. No actual matter was harmed in the course of either explosion

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    Coragyps
    Member (Idle past 734 days)
    Posts: 5553
    From: Snyder, Texas, USA
    Joined: 11-12-2002


    Message 134 of 243 (453034)
    02-01-2008 9:20 AM
    Reply to: Message 132 by Trixie
    02-01-2008 8:59 AM


    Re: 0.6 grams of mass lost at Hiroshima
    Also, given what Fat Boy did, it might be useful to tranlate the 5.4x1013 Joules into what that would do.
    Lessee.....it would heat 34,000,000 gallons of water from 32F to 212F.
    Or it would provide fifteen million kilowatt-hours of electricity to homes.

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    Rahvin
    Member
    Posts: 4032
    Joined: 07-01-2005
    Member Rating: 9.2


    Message 135 of 243 (453036)
    02-01-2008 9:21 AM
    Reply to: Message 133 by cavediver
    02-01-2008 9:14 AM


    Re: 0.6 grams of mass lost at Hiroshima
    In both nuclear explosions and chemical explosuions, the energy released comes from the binding energy - binding energy of the nucleus and binding energy of the atoms/molecules.
    This is different from antimatter/matter annihilation, however, where the particles are actually fully transformed into high-energy photons. Is that correct?

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