AQA GCSE Fusion reactions in stars (Physics)
Fusion reactions in stars
Stars such as our Sun contain a mixture of hydrogen and helium.
In a nuclear fusion reaction, the hydrogen is converted into helium.
This is carried out through a series of reactions, rather than a single reaction.
You do not need to know the individual stages, you just need to know that overall hydrogen is fused to form helium.
The individual stages have been given to provide slightly more detail.
1st Stage
In our Sun, two hydrogen nuclei are fused to form heavy hydrogen nuclei and energy is released.
2nd Stage
Hydrogen nuclei fuses with heavy hydrogen nuclei to form a helium nucleus.
3rd stage
Two of the Helium-3 nuclei will fuse to form Helium-4 nuclei and hydrogen nuclei, also releasing energy.
In stars of a similar size to our sun, fusion occurs to form elements that do not have a mass greater than iron.
In stars with a mass greater than our Sun, fusion will occur to form elements heavier than iron. During the supernova stage of the life cycle of a massive star, the core is compressed so much that heavier elements such as uranium are formed.
Practice Questions
1.Name the process which allows for the formation of carbon in stars
2. Write a nuclear fusion equation to explain how three helium-4 nuclei could fuse to form a carbon 12 nucleus.
3. Explain how very heavy elements such as uranium are formed by stars.
Absorption and Emission of EM Radiation
JJ Thomson and Plum pudding model
Ernest Rutherford and the Nuclear Model
Niels Bohr changing the Nuclear Model
Discovering the Proton and Neutron
Measuring radiation from radioactivity
Radiation types and properties
Random nature of radioactive decay
Radioactive contamination or irradiation
Hazards of contamination and irradiation
Studies on the effects of radiation on humans
Different half lives of radioactive isotopes
Nuclear Fission Chain Reaction
Writing nuclear fission equations
Drawing ray diagrams for a concave lens
Drawing Ray Diagram to produce a virtual image for a convex lens
Drawing ray diagram to produce a real image for a convex lens.
Specular and Diffuse Reflection
Seeing Coloured Objects Part 2
Viewing objects through coloured filters
Transparent, Translucent and Opaque