The Forces Within the Nucleus
The stability of an atomic nucleus is a constant battle between powerful competing forces. This section explores why some nuclei are stable while others decay. Click on the forces to learn more.
Strong Nuclear Force
The strongest force, acting over extremely short distances. It’s the “glue” that binds protons and neutrons together, overcoming their mutual repulsion.
Electrostatic Force
The repulsive force between all positively charged protons. It is weaker than the strong force but acts over a long range, destabilising large nuclei.
Weak Nuclear Force
Responsible for transformations within the nucleus. It allows a neutron to change into a proton (or vice versa), mediating the process of beta decay.
Properties of Nuclear Radiations
Unstable nuclei release energy by emitting radiation. This section explores the distinct properties of alpha, beta, and gamma radiation. Note the inverse relationship between ionising ability and penetrating power.
Alpha (α) Particle
- Nature: Helium Nucleus (42He)
- Ionising Power: High
- Penetration: Low (stopped by paper)
Beta (β) Particle
- Nature: Electron/Positron (0-1e)
- Ionising Power: Medium
- Penetration: Medium (stopped by Al)
Gamma (γ) Ray
- Nature: High-energy Photon
- Ionising Power: Low
- Penetration: High (needs lead)
Radioactive Decay & Half-Life
Radioactive decay is random for a single nucleus but predictable for a large sample. Use the slider to see how a 100g sample decays over time. Half-life (t1/2) is the time for the sample to reduce by half.
Interactive Half-Life Simulator
Biological Effects & Dose
Ionising radiation can be both a hazard and a medical tool. This section explores its effects and how we quantify the dose. The risk depends on radiation type and location (external vs. internal).
Interactive Dose Calculator
Absorbed Dose (D): Gy
Equivalent Dose (H): Sv
E=mc² & The Binding Energy Curve
Einstein’s E=mc2 shows that mass is a form of energy. Nuclear reactions release energy by converting a tiny amount of mass. The Binding Energy Curve explains why both splitting heavy atoms (fission) and joining light atoms (fusion) release energy.
Interactive Binding Energy Curve
A higher binding energy per nucleon means a more stable nucleus. Both fission and fusion move “uphill” towards Iron-56, the peak of stability. Hover over the curve to learn more.
Nuclear Fission & Fusion
Fission is the splitting of a heavy nucleus, used in power plants. Fusion is the joining of light nuclei, powering the sun. Explore the fission chain reaction below.
Fission Chain Reaction
Case Study: Nuclear Energy for Australia
Is nuclear power a viable energy source for Australia? This is a complex debate with strong arguments on both sides, involving science, economics, and public policy. Use the tabs to explore the debate.
Barriers to Nuclear Power
- Cost: CSIRO analysis finds nuclear power to be significantly more expensive than renewables like solar and wind.
- Timeframe: A minimum 15-year lead time means it cannot solve immediate energy or climate goals.
- Waste: Australia has no permanent facility for high-level radioactive waste, a major technical and political challenge.
- Public Perception: Past accidents have created significant public and political opposition.
- Water Use: Reactors require huge amounts of cooling water, a major issue for a dry continent like Australia.
