Video Transcript
Which of the following statements correctly contrasts nuclear fusion and nuclear fission? (A) In nuclear fission, large nuclei split, while in nuclear fusion, small nuclei combine. Or (B) in nuclear fusion, large nuclei split, while in nuclear fission, small nuclei combine.
Nuclear fusion and nuclear fission are both processes which release a lot of energy. We can see from options (A) and (B) that one of these processes involves large nuclei splitting and the other involves small nuclei combining. Large nuclei split when they are unstable. Uranium-236 is an example of an unstable isotope. Uranium-236 can be formed by bombarding uranium-235 with slow-moving neutrons. As uranium-236 is unstable, it will split into two smaller nuclei such as barium and krypton. It will also release three neutrons and nuclear energy.
An example of two nuclei combining is the combination of two hydrogen nuclei to form a helium nucleus and nuclear energy. Combining nuclei requires much higher temperatures than splitting nuclei. It also requires high pressures. The combination of two hydrogen nuclei to form helium occurs in the Sun.
So we have seen how large nuclei split and how small nuclei combine. But we need to know which one is fission and which one is fusion. During the combination of two small nuclei, the nuclei are fused together. So this process is nuclear fusion. This means that the splitting of large nuclei must be nuclear fission.
So the answer to the question “Which of the following statements correctly contrasts nuclear fusion and nuclear fission?” is (A) in nuclear fission, large nuclei split, while in nuclear fusion, small nuclei combine.
