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Author  Topic: Misconceptions of E=MC^2  
Trixie Member (Idle past 2126 days) Posts: 1011 From: Edinburgh Joined: 
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 5.4x10^{13} 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=mc^{2} 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


Trixie Member (Idle past 2126 days) Posts: 1011 From: Edinburgh Joined: 
Perfect. The reason I've asked for this is cos Heinrik asked if E=mc^{2} had been tested. So, if the application of the formula to the amount of material used up at Hiroshima results in the amount of energy which would be required to do exactly what was done at Hiroshima, (avoiding what was done at Hiroshima to determine what that amount of energy would do cos otherwise we get circular again)then we have an application of the formula where it has been tested in the real world and found to be accurate, something that Heinrik is asking for. I'm just trying to get all of this into a format which Heinrik will understand. Thanks for your patience guys. Oh, and my explanation for "Fat Boy" is that I was listening to Fatboy Slim (Right Here, Right Now) while I was writing my post and my brain shortcircuited LOL


Trixie Member (Idle past 2126 days) Posts: 1011 From: Edinburgh Joined: 
Sorry I missed this in my previous post. This is exactly the sort of thing I meant. It means we get "real world" equivalents that nonscientists can relate to.


Trixie Member (Idle past 2126 days) Posts: 1011 From: Edinburgh Joined: 
Heinrik, do my posts help any? You'll only have to check back a few posts. I'm a complete physics turniphead so I've tried to get explanations from the physicists that avoid the formulae and include reallife situations. If you start at;
www.evcforum.net/cgibin/dm.cgi?action=msg&f=11&t=332&m=121#132 >www.evcforum.net/cgibin/dm.cgi?action=msg&f=11&t=332&m=121#132">http://www.evcforum.net/cgibin/dm.cgi?action=msg&f=11&t=332&m=121#132 and then follow on from there you'll see what I tried to do. Having said that, it may be so much gobbldegook. I must admit, I keep having to reboot my brain to understand even my own posts on this subject :o


Trixie Member (Idle past 2126 days) Posts: 1011 From: Edinburgh Joined: 
Treat the equation as you would any algebraic equation. Remember, way back when Modulus plugged numbers into it
Imagine if e=2 x 3^{2}, then e=18 It follows on that 2=18/3^{2} and also 3^{2}= 18/2 it's just pure algebra, the way you learned that if you have x + 2 = 9 you can transform the equation to read x + 2  2 = 9  2 I just subtracted 2 from both sides,so I can have the unknown on one side of the equals and knowns on the other side. Simplifying we get x = 92 The reason I've picked such a simple one without squares, products etc is because you actually see it in action. You know the answer before you start, so each step of the process makes perfect sense and if you don't end up with the right answer, you know you've done something wrong. It doesn't matter how comlex an equation is or the complexity of the theory it's describing, the basic rules of algeba apply


Trixie Member (Idle past 2126 days) Posts: 1011 From: Edinburgh Joined: 
All the equation does is provide a means by which you can work out the theoretical amount of energy that can be released for a given mass of a substance. While we can't measure energy directly, e can measure mass, so if we plug a value for mass into the equation at m we can then calculate the emount of energy since c is constant.
So, the only variables in the equation are mass and energy. The amount of energy is dependent on the amount of mass, similarly, if you know the amount of energy, you can calculate back to the amount of mass it came from. So if you have a mass of 3g you will get a different answer than if you have a mass of 6g. That's why the equation doesn't have a specific number for m or E. They are the "variables" so you can work out the energy for any given mass. Using m=E/c^{2} means yu can work out the mass for any given value of E I don't want to get into the complication of the various units that are used. At the risk of oversimplifying (and please don't be offended, this is how I have to think all the time, especially when I'm doing calculations for dilution factors for various chemical solutions) The number of oranges in my shopping bag is equal to the number of oranges I buy minus the number of oranges my son ate on the way home from the shops. Since I only allow him 2 oranges (because of the dreadful effects oranges have on his innards, but I better not go into that :laugh: ), then the number of oranges I manage to get home with will be the number I bought minus 2, and 2 will always be constant (given his infamous innards) So if F is the number that finally make it into the fruitbowl, and b is the number I buy I can express it as an equation; F=b2 If b=6 then F=4 The reason b is used and not a number is that you can then plug any number in and the value of F depends on the value of b which is variable (depending on how much money I have on give day). Edited by Trixie, : You don't want to know, believe me


Trixie Member (Idle past 2126 days) Posts: 1011 From: Edinburgh Joined: 
Heinrik, the post linked to below may help you to understand where Parasomnium is coming from (and molbiogirl)
www.evcforum.net/cgibin/dm.cgi?action=msg&f=25&t=3453&m=1 >www.evcforum.net/cgibin/dm.cgi?action=msg&f=25&t=3453&m=1">http://www.evcforum.net/cgibin/dm.cgi?action=msg&f=25&t=3453&m=1 It's a PNT and the entire text reads
That post on 29.1.08 is the latest in a long line of posts like this. This sort of thing comes up again and again and does become tedious. For this reason, if even a hint is present that a poster might think in this way, it's corrected ASAP because it really is a huge barrier to understanding science. I also think there has been a misunderstanding by many since the beginning of this thread and I can include myself in that. I really thouht that the topic was to discuss the misconceptions that scientists have with E=mc^{2}. It became apparent as the discussion progressed that you wanted to discuss your misconceptions. Don't take this the wrong way, I am not trying to criticise you, I'm only trying to offer an explanation. It's not on topic either, but I'm hoping that it can pour oil on troubled waters and let you continue getting info from Modulus.


Trixie Member (Idle past 2126 days) Posts: 1011 From: Edinburgh Joined: 
Yes, I think you have the right to do that. This thread has been a terrific one and I hope it continues  you do know that you got a nomination for post of the month and it was seconded by Quetzal? Sadly, you don't get any sweeties or anything for it (I asked, but none were forthcoming), just the knowledge that a post of yours has contributed in a big way to this forum.
Admin  I promise this is the very, very last off topic post. It's here because it does flow nicely through the thread and the thread demonstrates so well where ALL of us can improve our communication. Edited by Trixie, : My little spiel to Admin is so obviously off the mark that I felt I should point it out as being a total load of bullshit, with the exception of it being the last offtopic post from me.



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