It's my first time here, so I'm not sure if this is the right place to post it. If I post it in the wrong section, then I'm sorry.

Anyways, I just have a curious question. Based on this video I watched --> ""

at around 1:40:42 , I really want to know how she actually calculated the amount of energy lost during the nuclear fission of the uranium atom by using E=mc^2. I'm just curious that's all because the video doesn't show the actual calculation. So, if one of you guys can show the process of the mathematics, that would be great!

She says what calculation she's doing, but I can't understand it with her accent. Somehow she's calculating how much mass is lost in the fission process, perhaps by knowing the mass of the uranium and the products and simply subtracting. Then you just plug that number into e=mc^2. Here's an example: http://www.bbc.co.uk/bitesize/higher/physics/radiation/nuclear_reactions/revision/2/

She says clearly that the two nuclei (produced in the fission) are lighter than the original nucleus of uranium by about 1/5 of the proton in mass. When you know this number it is just plug and chug

Yeah - it was what she said right before that, before she calculated that result that I couldn't understand. Sounds like "let me do a packing friction calculation", but I don't think that's right....

LISE MEITNER: "Wait, let me do a packing fraction calculation. The two nuclei are lighter than the original uranium nucleus by about one-fifth of a proton in mass".
[ref: Nova transcript]

I can't find the original letter that sparked the conversation, sent on 19 December, 1938, but I did find the paper published a few months later:

I plugged and chugged and came up with 169 mev, based on wiki's most convenient: U236 fission into Ba141 + Kr92 + 3 Neutrons image

Specifics available upon request.

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And given that I'm prone to forgetting where everything is:
file: pf.random.homework.problems.numbers
tab: fission of U236