7.2.7
Nuclear Fission - Uncontrolled Chain Reaction
Nuclear Fission - Uncontrolled Chain Reaction
Nuclear Fission - Uncontrolled Chain Reaction
If nuclear fission is not controlled, then the rate of nuclear fission can become faster and faster. This starts a chain reaction where each stage of fission produces more and more energy. This could lead to an explosion.


Atom bombs
Atom bombs
- Atom bombs use these chain reactions to create large explosions and release lots of energy.
1Forces & Motion
1.1Basics of Motion
1.1.1Average Speed
1.1.2Acceleration
1.1.3Distance & Displacement
1.1.4Velocity
1.1.5Adding Vectors
1.1.6Distance-Time Graphs
1.1.7Speed-Time Graphs 1
1.1.8Speed-Time Graphs 2
1.1.9Initial & Final Speed, Acceleration, Distance
1.1.10Average Speed - Calculations
1.1.11Acceleration - Calculations
1.1.12Uniform Acceleration - Calculations
1.1.13Grade 9 - Motion
1.1.14Exam-Style Questions - Graphs of Motion
1.2Forces
1.3Effects of Forces
1.3.1Momentum - No Impulse
1.3.2Momentum
1.3.3Momentum: Law of Conservation
1.3.4Force & Momentum Change
1.3.5Momentum - Safety
1.3.6Change in Momentum - Calculations
1.3.7Momentum - Calculations
1.3.8Mass
1.3.9Weight
1.3.10Centre of Mass
1.3.11Gravity - Calculations
1.3.12Free Fall
1.3.13Air Resistance & Friction
1.3.14Graphs of Motion with Air Resistance
1.3.15Turning Effect
1.3.16Moments
1.3.17Equilibrium
1.3.18Moments - Calculations
1.3.19Exam-Style Questions - Moments
1.4Stopping Distance
1.5Forces & Elasticity
1.5.1Stretching, Bending & Compressing
1.5.2Elastic Deformation vs Inelastic Deformation
1.5.3Hooke's Law
1.5.4Hooke's Law - Equation
1.5.5Hooke's Law - Spring Experiments
1.5.6Hooke's Law - Calculations
1.5.7Elastic Potential - Calculations
1.5.8End of Topic Test - Forces
1.5.9Exam-Style Questions - Elastic Potential
2Electricity
2.1Electricity in Homes
2.2Current & Potential Difference
2.3Resistance & Power
2.4Electric Circuits
2.4.1Circuit Diagrams
2.4.2Circuit Symbols
2.4.3Diodes
2.4.4LDRs & Thermistors
2.4.5Series Circuits
2.4.6Resistors in Series
2.4.7Series Circuits - Calculations
2.4.8Parallel Circuits
2.4.9Parallel Circuits in Practice
2.4.10End of Topic Test - Electricity
2.4.11Grade 9 - Circuits
2.4.12Exam-Style Questions - Electrical Circuits
3Waves
3.1Wave Basics
3.2Waves at a Boundary
3.3Electromagnetic Spectrum
3.4Sound Waves
3.5Communications
4Energy Resources & Energy Transfers
4.1Energy Changes
4.1.1Energy Stores
4.1.2Conservation of Energy
4.1.3Examples of Energy Conversion
4.1.4Kinetic Energy Stored
4.1.5Gravitational Potential Energy Stored
4.1.6Elastic Potential Energy Stored
4.1.7Changes in Kinetic Energy - Calculations
4.1.8Changes in GPE - Calculations
4.1.9Changes in EPE - Calculations
4.1.10Mechanical Work Done
4.1.11Mechanical Work Done - Equation
4.1.12Power
4.1.13Mechanical Work - Calculations
4.1.14Electrical Work Done- Calculations
4.2Energy Losses & Efficiency
4.3Energy Resources
5Solids, Liquids & Gases
5.1Density & Pressure
5.2Changing State
6Magnetism & Electromagnetism
6.1Magnetism
6.2Electromagnetism
6.3Electromagnetic Induction
6.4Transformers
6.4.1Transformers
6.4.2Transformer Equation
6.4.3Step-Up & Step-Down Transformers
6.4.4Principles of Transformer Operation
6.4.5High-Voltage Transmission & Transformers
6.4.6Transformers - Calculations
6.4.7Transformers 2 - Calculations
6.4.8Energy in Transformers
6.4.9Power Losses in Cables
6.4.10End of Topic Test - Magnetism
6.4.11Grade 9 - Transformers
6.4.12Exam-Style Questions - Transformers
7Radioactivity & Particles
7.1Atoms
7.2Radioactivity
7.2.1Radioactive Decay
7.2.2Types of Radiation
7.2.3Three Types of Emission
7.2.4Ionising vs Penetration
7.2.5Nuclear Fission
7.2.6Nuclear Reactors
7.2.7Nuclear Fission - Uncontrolled Chain Reaction
7.2.8Radioactive Decay
7.2.9Decay Equations
7.2.10Nuclear Fission Equation
7.2.11Half Life & Background Radiation
7.2.12Measuring Half-Life From a Graph
7.2.13Background Radiation
7.2.14Practical Applications of Radiation
7.2.15Ions & Ionising Radiation
7.2.16Safety Precautions
7.2.17Peer Review
7.2.18End of Topic Test - Radioactivity & Particles
7.2.19Grade 9 - Radioactivity & Particles
7.2.20Exam-Style Questions - Radioactive Decay
8Astrophysics
8.1Motion in the Universe
8.2Evolution of Stars
Jump to other topics
1Forces & Motion
1.1Basics of Motion
1.1.1Average Speed
1.1.2Acceleration
1.1.3Distance & Displacement
1.1.4Velocity
1.1.5Adding Vectors
1.1.6Distance-Time Graphs
1.1.7Speed-Time Graphs 1
1.1.8Speed-Time Graphs 2
1.1.9Initial & Final Speed, Acceleration, Distance
1.1.10Average Speed - Calculations
1.1.11Acceleration - Calculations
1.1.12Uniform Acceleration - Calculations
1.1.13Grade 9 - Motion
1.1.14Exam-Style Questions - Graphs of Motion
1.2Forces
1.3Effects of Forces
1.3.1Momentum - No Impulse
1.3.2Momentum
1.3.3Momentum: Law of Conservation
1.3.4Force & Momentum Change
1.3.5Momentum - Safety
1.3.6Change in Momentum - Calculations
1.3.7Momentum - Calculations
1.3.8Mass
1.3.9Weight
1.3.10Centre of Mass
1.3.11Gravity - Calculations
1.3.12Free Fall
1.3.13Air Resistance & Friction
1.3.14Graphs of Motion with Air Resistance
1.3.15Turning Effect
1.3.16Moments
1.3.17Equilibrium
1.3.18Moments - Calculations
1.3.19Exam-Style Questions - Moments
1.4Stopping Distance
1.5Forces & Elasticity
1.5.1Stretching, Bending & Compressing
1.5.2Elastic Deformation vs Inelastic Deformation
1.5.3Hooke's Law
1.5.4Hooke's Law - Equation
1.5.5Hooke's Law - Spring Experiments
1.5.6Hooke's Law - Calculations
1.5.7Elastic Potential - Calculations
1.5.8End of Topic Test - Forces
1.5.9Exam-Style Questions - Elastic Potential
2Electricity
2.1Electricity in Homes
2.2Current & Potential Difference
2.3Resistance & Power
2.4Electric Circuits
2.4.1Circuit Diagrams
2.4.2Circuit Symbols
2.4.3Diodes
2.4.4LDRs & Thermistors
2.4.5Series Circuits
2.4.6Resistors in Series
2.4.7Series Circuits - Calculations
2.4.8Parallel Circuits
2.4.9Parallel Circuits in Practice
2.4.10End of Topic Test - Electricity
2.4.11Grade 9 - Circuits
2.4.12Exam-Style Questions - Electrical Circuits
3Waves
3.1Wave Basics
3.2Waves at a Boundary
3.3Electromagnetic Spectrum
3.4Sound Waves
3.5Communications
4Energy Resources & Energy Transfers
4.1Energy Changes
4.1.1Energy Stores
4.1.2Conservation of Energy
4.1.3Examples of Energy Conversion
4.1.4Kinetic Energy Stored
4.1.5Gravitational Potential Energy Stored
4.1.6Elastic Potential Energy Stored
4.1.7Changes in Kinetic Energy - Calculations
4.1.8Changes in GPE - Calculations
4.1.9Changes in EPE - Calculations
4.1.10Mechanical Work Done
4.1.11Mechanical Work Done - Equation
4.1.12Power
4.1.13Mechanical Work - Calculations
4.1.14Electrical Work Done- Calculations
4.2Energy Losses & Efficiency
4.3Energy Resources
5Solids, Liquids & Gases
5.1Density & Pressure
5.2Changing State
6Magnetism & Electromagnetism
6.1Magnetism
6.2Electromagnetism
6.3Electromagnetic Induction
6.4Transformers
6.4.1Transformers
6.4.2Transformer Equation
6.4.3Step-Up & Step-Down Transformers
6.4.4Principles of Transformer Operation
6.4.5High-Voltage Transmission & Transformers
6.4.6Transformers - Calculations
6.4.7Transformers 2 - Calculations
6.4.8Energy in Transformers
6.4.9Power Losses in Cables
6.4.10End of Topic Test - Magnetism
6.4.11Grade 9 - Transformers
6.4.12Exam-Style Questions - Transformers
7Radioactivity & Particles
7.1Atoms
7.2Radioactivity
7.2.1Radioactive Decay
7.2.2Types of Radiation
7.2.3Three Types of Emission
7.2.4Ionising vs Penetration
7.2.5Nuclear Fission
7.2.6Nuclear Reactors
7.2.7Nuclear Fission - Uncontrolled Chain Reaction
7.2.8Radioactive Decay
7.2.9Decay Equations
7.2.10Nuclear Fission Equation
7.2.11Half Life & Background Radiation
7.2.12Measuring Half-Life From a Graph
7.2.13Background Radiation
7.2.14Practical Applications of Radiation
7.2.15Ions & Ionising Radiation
7.2.16Safety Precautions
7.2.17Peer Review
7.2.18End of Topic Test - Radioactivity & Particles
7.2.19Grade 9 - Radioactivity & Particles
7.2.20Exam-Style Questions - Radioactive Decay
8Astrophysics
8.1Motion in the Universe
8.2Evolution of Stars
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