Nuclear Fission Diagrams (AQA GCSE Physics)

The diagram shows the nuclear fission process for an atom of uranium-235.

Complete the diagram to show how the fission process starts a chain reaction.

Answer:

Step 1: Draw the neutrons to show that they hit other U-235 nuclei

• It is the neutrons hitting the uranium-235 nuclei which causes the fission reactions

• The daughter nuclei do not need to be shown, only the neutrons and uranium-235 nuclei

Step 2: Draw the splitting of the U-235 nuclei to show they produce two or more neutrons

• The number of neutrons increases with each fission reaction

• Each reaction requires one neutron but releases two

• More reactions happen as the number of neutrons increases

You need to be able to draw and interpret different diagrams of nuclear fission and chain reactions. Generally, things move to the right as time goes on in these diagrams, but it is important to read all the information carefully on questions like this. If you have to draw a diagram in an exam remember that the clarity of the information is important, not how pretty it looks!