Nuclear fusion · Grade 11

In Grade 11 you get fluent with: fusion in stars, why fusion needs huge temperatures, and balancing fusion equations.

In fusion, two light nuclei, such as isotopes of hydrogen, join to make a heavier nucleus, releasing energy. Nuclei are positive and repel each other, so fusion only happens at the huge temperatures and pressures inside stars. Fusion of hydrogen into helium powers the Sun.

Key facts

• Fusion: light nuclei (e.g. hydrogen) join to make heavier ones; it needs extreme temperature and pressure.
• The Sun fuses hydrogen into helium in its core: it is not burning like a fire.
• Mass numbers and atomic numbers must balance on both sides of a nuclear equation.

Worked examples

Other years

• Nuclear fusion · Grade 10
• Nuclear fusion · Grade 12