Discussion of calculation of Physics Cost-Saving Tips
- At the moment the calculation for 2649: Physics Cost-Saving Tips performed by SqueakSquawk4 is included in the explanation of said comic. Here this can be discussed. --Kynde (talk) 07:01, 25 July 2022 (UTC)
Helium-2 has a half-life of roughly 10-9 seconds, or one nanosecond, and a mean life of roughly 1.44 nanoseconds. For context, light travels at roughly 30 cm per nanosecond. This means that on a human scale the energy is released all at once, and we only have to calculate total energy released, and not worry about time taken.
A moderately-sized balloon might have a diameter of 12 inches. Some calculations give this a volume of roughly 14.83 liters (assuming a spherical balloon.) If the balloon is at 1 atmosphere of pressure at 25 degrees Celsius, then there would be 0.6058 mol in the balloon, mean that there is 0.6058 * 6.022×1023 atoms, or 364,800,000,000,000,000,000,000 atoms.
To recap, a helium-2 atom decaying results in 1.25 MeV of energy, and there are roughly 365 sextillion atoms in a balloon.
Every atom will create 1.25 MeV of energy, and therefore 365 sextillion atoms will create 365*1.25 sextillion, or 456 sextillion MeV. Interestingly, this is equal to 456 nonillion electron volts, or 4.56 megayottaelectron-volts. 456 sextillion megaelectron-volts is also equal to roughly 73,100 megajoules, or 17.4 tons of TNT equivalent.
That looks great! Sorry I can't talk to you on your talk page, it hasn't been created and I've always been too lazy to make an autoconfimed user. I hope you're okay with the changes in this edit. Do you mind if we subst: this into the collapse box on 2649 so it can be cleaned up and formatted there? Thanks for looking all that up. 18.104.22.168 14:37, 24 July 2022 (UTC)
- What actually is Subst-ing? SqueakSquawk4 (talk) 15:51, 24 July 2022 (UTC)
- It just means copying it instead of transcluding it like a template. The advantage is it's not dependent on your userpage which is kind of nonstandard and awkward, but the disadvantage is that edits in one place won't show up in the other. mw:Help:Substitution. 22.214.171.124 16:12, 24 July 2022 (UTC)
- Hi SqueakSquawk4. I cannot validate your calculation, but given all the discussion about it, I think it is valid to include in the explanation. It is a new way to include stuff on explain xkcd, so I'm not sure about that version, but I will not oppose it. If others agree with your calculations, I think it is a great effort by you. Thanks. Have added a header, so the next who wish to write to you on other subjects, can make a new header, so not to mix up the discussions. And also included the calculation at the top, so everyone coming here knows what the fuss is about. Good job! ;-) --Kynde (talk) 07:01, 25 July 2022 (UTC)
... First, I just noticed, why did you go from 1.25 to 1.35 to 1.5 MeV? Which figure did you use for the total energy product? Fixed math. 126.96.36.199 16:53, 24 July 2022 (UTC)