6.9 - Nuclear Fusion

• What is nuclear fusion?

  Joining two lighter nuclei to form a larger nucleus
• What happens when two hydrogen nuclei fuse?

  They form helium-3 and release energy
• What fuels stars?

  Nuclear fusion
• How are elements heavier than hydrogen formed?

  Through nuclear fusion processes
• Why does fusion produce large amounts of energy?

  Mass is converted to energy during fusion
• What happens to the mass of helium nuclei formed from hydrogen fusion?

  It is slightly lighter than the original mass
• What is Einstein's equation related to fusion energy?

  Energy equals mass times the speed of light squared
• How do you calculate energy from mass loss in fusion?

  Multiply mass loss by $c^2$
• What is the approximate value of $c^2$?


  About $9 \times 10^{16}$
• What is a significant advantage of nuclear fusion?

  It produces no radioactive waste
• What is needed as fuel for nuclear fusion?

  Hydrogen
• What conditions are required for nuclear fusion to occur?

  High temperatures and pressures
• At what temperature does nuclear fusion occur?

  About 10 million degrees Celsius
• Why can't we currently perform nuclear fusion on Earth?

  It requires extremely high temperatures and pressures
• What is the focus of current research regarding nuclear fusion?

  Discovering how to achieve fusion on Earth
• How does nuclear fusion differ from nuclear fission?

  Fusion fuses light nuclei; fission splits heavy nuclei
• What is produced during nuclear fission?

  Two smaller nuclei and energy
• Which process is used to generate electricity on Earth?

  Nuclear fission
• What are the key differences between nuclear fusion and nuclear fission?

  • Fusion: Fuses light nuclei to form heavier nuclei
  • Fission: Splits large unstable nuclei into smaller nuclei
  • Fusion releases more energy than fission
  • Fusion occurs in stars; fission is used on Earth
• What are the advantages and challenges of nuclear fusion?

  Advantages:

  • Produces no radioactive waste
  • Abundant fuel supply (hydrogen)
  • Releases vast amounts of energy

  
  

  Challenges:

  • Requires extremely high temperatures and pressures
  • Currently not feasible on Earth
  • Ongoing research needed for practical application
• Nuclear fusion is the fusing of two lighter nuclei to make a single heavier nucleus. When this occurs, a lot of energy is emitted in the form of electromagnetic radiation.
• Nuclear fusion releases massive amounts of energy.

  Where does this energy come from?

  Some of the mass converts to energy
• Nuclear fusion occurs in stars, and is the reason why stars give off so much energy.

  Most of the fusion occurring in stars is hydrogen nuclei fusing to become helium nuclei.
• Why does fusion only happen at very high temperatures and pressures?

  To overcome the repulsion of the positively charged nuclei 
• Are the following statements describing nuclear 'fission' or nuclear 'fusion'?

  • Two small light nuclei fusing to become a single heavier nuclei: fusion
  • A single large nuclei splitting to become two smaller nuclei: fission
  • Will produce radioactive waste: fission
  • Only happens at very high temperatures and pressures: fusion