What to notice
The antineutrino restores electron-lepton number and can carry energy and momentum.
Build · test · inspect · explain
Particle & Atom Lab
Reconstruct the event, find the missing particle and use the evidence to decide what nature allows.
n
p
e⁻
?
pnpn
Specification lens
Choose your course
AQA 7407/7408 · 3.2.1 ParticlesFull particle, quark, exchange-particle and conservation-law lens.
Weak interaction · beta-minus decay
Event chamber
Paused
Current event
n → p + e⁻ + ?
hadron / nucleus
lepton
antimatter
photon / energy
A neutron decays into a proton, electron and an empty particle slot.
Particle tray
Choose the missing particle
Turn evidence into physics
Explain the event
Complete explanation
Choose and check a particle to reveal the complete explanation.
Watch the misconception
A neutrino and an antineutrino are not interchangeable.
What this scientific model simplifies
Tracks and momenta are schematic. A numerical energy–momentum check would require a complete measured event.
Protons · neutrons · electrons · real isotope data
Atom Builder
Assemble atoms from individual particles, move through the periodic table and watch unstable or metastable nuclei transform.
AQA 7408 · 3.8.1.3–4 Nuclear instabilityEmpty chamber · add a proton
Atom chamber
Ready
Drop particles into the chamber
The chamber is empty. Add a proton to create hydrogen.
Predict → observe → explain
Nucleus clock
WatchingNo nucleus
Before the decay
Predict the daughter
Build an unstable isotope, then predict how its mass number A and atomic number Z will change.
Choose an answer before revealing the equation.
Run one random nucleus
Observe the clock
Likely modeNo decay
—not applicablesampled lifetime
The screen clock is accelerated, but the instant of decay is still random.
Use the evidence
Explain the change
Nuclear equationBuild an evaluated isotope to inspect its decay.
The explanation appears after a correct prediction or an observed decay.
Charge0 = +1 − 1 + 0
Baryon number1 = 1 + 0 + 0
Electron lepton no.0 = 0 + 1 − 1
Proton number map
Periodic table position
Add protons to move across the periodic table.
Transformation record
Decay trail
- Completed decays will appear here with their daughter nucleus.
Ground-state half-lives and decay modes: IAEA LiveChart of Nuclides. Free-neutron mean life: Particle Data Group. Electron shells are schematic.