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If you need to put more energy into making a bigger nucleus, shouldn't bigger nuclei have more energy that can be released? How does putting energy into making hydrogen into helium even release that much more energy?
Binding energy - http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin.html#c1questionpost said:If you need to put more energy into making a bigger nucleus, shouldn't bigger nuclei have more energy that can be released? How does putting energy into making hydrogen into helium even release that much more energy?
Astronuc said:Binding energy - http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin.html#c1
Binding energy is the energy required to pull a nucleus APART, not hold it together.questionpost said:I still don't completely understand. You have a binding energy, and that's the energy required to hold a nucleus together, and you put tons of energy into making a bigger nucleus...but after a certain point the bonds between nuclei are weaker which means not as much energy was put into making them?
Yes, but not in general more than all other combinations of nucleons. There is more total binding energy in U-238 than in 238 separate protons and neutrons, sure, but not more than Th-234 + He4.questionpost said:Even if you split them though, isn't it a total of more energy within the bonds of a bigger nucleus still bigger than whatever bonding energy is in hydrogen?
questionpost said:Or perhaps because with fission, you can only break atoms down into specific pieces which take up most of the energy within the binding of the nuclei yielded, and with simply putting a lot of energy into fusing just two hydrogen atoms together, the extra neutron doesn't take up as much binding energy so there is more energy available to be turned into kinetic and electro-magnetic energy?
kurros said:I'm not quite sure what you are talking about, but perhaps it is the activation energy that is confusing you. You have to overcome the Coulomb repulsion between parent nuclei in order to get them close enough to fuse, but the energy you spend doing this does not go into the binding energy in the new nucleus.
questionpost said:So your telling me that if I put energy into building a bigger nucleus and I don't get that amount energy back, the energy didn't go into holding a bigger nucleus together and instead it just... transforms into...photons? Or disappears?
questionpost said:Also, how is the energy required to pull it apart not in some way related to the energy that's holding the nucleus together? Isn't that the force you have to overcome?
kurros said:Force and energy are different. It takes force to hold you on the earth, but no energy.
questionpost said:I think I'm getting a better picture with the fission efficiency itself, but about this statement, doesn't it take some kind of at least potential energy to exist in a state that isn't at the lowest possible state?
questionpost said:If you need to put more energy into making a bigger nucleus, shouldn't bigger nuclei have more energy that can be released? How does putting energy into making hydrogen into helium even release that much more energy?
Fusion is more efficient than fission because it releases significantly more energy per unit mass. This is because fusion reactions involve the merging of two smaller nuclei to form a larger one, while fission reactions involve the splitting of a larger nucleus into smaller ones. The fusion of nuclei results in the formation of heavier and more stable elements, which releases a larger amount of energy.
The efficiency of fusion is much higher than fission. While fission reactions typically release only about 0.1% of the total mass as energy, fusion reactions can release up to 3-4% of the total mass as energy. This makes fusion a much more efficient and sustainable energy source.
The efficiency of fusion is influenced by several factors, including the temperature and density of the reactants, the type of fuel being used, and the confinement time of the reaction. In order for fusion to occur, the reactants must be heated to extremely high temperatures (over 100 million degrees Celsius) and compressed to high densities. The type of fuel used, such as deuterium and tritium, also plays a role in the efficiency of fusion reactions.
Fusion is considered a cleaner energy source compared to fission because it does not produce long-lived radioactive waste. While fission reactions produce radioactive waste that can remain hazardous for thousands of years, fusion reactions produce only short-lived radioactive waste that decays within a few decades. Additionally, fusion reactions do not emit greenhouse gases, making it a more environmentally friendly option.
One of the main challenges in achieving efficient fusion reactions is the high temperature and density requirements. To reach the temperatures required for fusion, powerful magnetic fields or intense lasers are needed to contain and heat the reactants. Another challenge is the difficulty in confining the reacting materials for a long enough time to sustain the reaction. Additionally, finding a suitable and reliable fuel source for fusion reactions is still a major obstacle in achieving efficient fusion.