2b.4 - Nuclear Fission and Fusion Flashcards
What is nuclear fission?
The splitting up of an atomic nuclei
How do nuclear reactions work? (4)
- Controlled chain reaction
- Atomic nuclei split up and release energy in the form of heat
- The steam heats energy
- Turns a turbine
What nuclei is used in nuclear fission?
Uranium-235 and/or plutonium-239
Explain the process of nuclear fission (4)
- Slow moving neutron is absorbed which makes it unstable, causing it to split
- Every split gives out two or three neutrons
- Splitting forms two smaller nuclei which are usually radioactive because wrong number of neutrons
- Releases lots of energy
What are products of nuclear fission? (3)
- Two smaller nuclei
- Energy
- Two or three neutrons
What are the pros of nuclear fission? (2)
- Produces lots of energy
- Fuel is cheap
What are the cons to nuclear fission? (4)
- Highly radioactive products - difficult to get rid of
- Maintenance costs are high
- Dismantling plant takes decades
- Radiation leaks
What is nuclear fusion?
The joining of small atomic nuclei
What are the advantages to nuclear fusion? (2)
- Gives lots of energy
- Doesn’t leave behind radioactive waste
What are the disadvantages to nuclear fusion? (3)
- Only happens at really high temperatures (10 million degrees)
- Needs an extremely strong magnetic field to store
- Uses more energy than is produced
What is the first stage in the life cycle of a low mass star?
Nebula - Clouds of gas and dust gather due to gravity
What is the first stage in the life cycle of a high mass star?
Nebula - Clouds of gas and dust gather due to gravity
What is formed in the nebula?
Protostars
What is the second stage for a low mass star?
Main stage star - fuse hydrogen into helium by nuclear fusion and burn for billions of years
What is the second stage for a high mass star?
Red Supergiant - The star runs out of hydrogen to fuel it so cools down and swell out
What is formed in a red supergiant?
Elements from helium to iron
What is the third stage for a low mass star?
Red giant stage
What is the third stage for a high mass star?
Supernova - A huge explosion where all elements heavier than iron are formed
Where are all elements heavier than iron formed?
Supernova
What is the forth stage for a low mass star?
White dwarf - No more light elements to use and it collapses
What happens to a high mass star after a supernova? (3)
- Elements and debris are flung into space
- Core collapses into a neutron star
- With enough mass it can become a black hole
What is the final stage for a low mass star?
Black dwarf
What did our solar system begin as?
A cloud of dust and gas
What was the first stage in the formation of the solar system?
A supernova disturbed the cloud
What was the second stage in the formation of the solar system?
The explosion made waves that squeezed the cloud
What was the third stage in the formation of the solar system?
The cloud began to collapse
What was the fourth stage in the formation of the solar system?
Gravity pulled the gas and dust together
What was the fifth stage in the formation of the solar system?
The cloud turned into a solar nebula and spun
What was the sixth stage in the formation of the solar system?
Solar nebula became hot and dense in the centre and the disk of gas and dusk at the edges was cool
What was the seventh stage in the formation of the solar system?
The disk grew thinner and continued spinning. The particles of dust and gas began to stick together
What was the eighth stage in the formation of the solar system?
Some groups of particles grew bigger , these later became moons and planets
