A-level: The physics and chemistry of meteorites

Twelve lessons that apply A-level physics, chemistry and geology to meteorites: gravitational fields and Kepler's laws, impact and entry physics, exponential decay and radiometric ages, mass spectrometry and oxygen isotopes, spectroscopy, igneous petrology, metallurgy, chirality and planetary defence.

Meteoritics is a working laboratory for A-level science. Each lesson in this course takes a topic from A-level physics, chemistry or geology, applies it to real meteorite research, and works through a quantitative problem at A-level standard. Where the ideas go beyond the A-level content, the lesson says so and keeps the maths within reach.

The lessons build in order from orbits and energy to isotopes, minerals and molecules. Each takes about an hour, plus the activity.

1. 1Gravitational fields and escapeHow does a rock leave Mars, the Moon or the asteroid Vesta? Newton's law of gravitation and the idea of gravitational potential give the escape velocity, and explain which bodies send us meteorites.
2. 2Orbits, Kepler's laws and resonancesKepler's third law connects an asteroid's distance from the Sun to its orbital period. Combined with Jupiter's gravity, it explains the gaps in the asteroid belt and the delivery of meteorites.
3. 3The energy of impacts and airburstsImpact energies range from a firecracker to the end of the dinosaurs. This lesson quantifies them, compares airbursts with cratering impacts, and introduces how crater size scales with energy.
4. 4Atmospheric entry and fragmentationA meteoroid is decelerated, heated and often shattered by the air. Simple models of drag and ram pressure explain where it breaks up and how much survives.
5. 5Exponential decay and radiometric agesRadioactive decay is exponential, and the decay equation can be turned into an age equation. This lesson derives it and uses uranium–lead to date a meteorite.
6. 6Extinct radionuclides and the first few million yearsSome radioactive isotopes present when the Solar System formed have long since decayed away. Their daughters date events in the first few million years with remarkable precision, and one of them melted the early asteroids.
7. 7Mass spectrometry and oxygen isotopesMass spectrometers measure isotope ratios to within about ten parts per million. Oxygen's three isotopes then sort meteorites into families and link them to their parent bodies.
8. 8Spectroscopy: matching meteorites to asteroidsSunlight reflected from an asteroid carries the absorption fingerprints of its minerals. Comparing those spectra with meteorites in the laboratory links meteorites to the asteroids they came from.
9. 9Igneous petrology of meteoritesMelting and crystallisation on asteroids, the Moon and Mars produced igneous rocks that geologists read with the same tools used on Earth. This lesson applies partial melting, fractional crystallisation and mineral chemistry.
10. 10The metallurgy of iron meteoritesIron meteorites are pieces of asteroid cores that cooled over millions of years. Their crystal structures and nickel distributions record cooling rates and the size of the bodies they came from.
11. 11Chirality and the origin of lifeLife uses left-handed amino acids almost exclusively. Some meteorites contain a small excess of left-handed forms, a clue to how this preference may have begun.
12. 12Shock, craters and deflecting an asteroidHypervelocity impacts generate shock pressures that transform minerals. This final lesson connects shock metamorphism, crater evidence and the momentum physics of deflecting an asteroid.

How it links to what you study

• Physics, gravitational fields: Newton's law of gravitation, field strength, escape velocity, circular orbits and Kepler's third law (lessons 1 and 2).
• Physics, mechanics and materials: kinetic energy, momentum and impulse, drag and pressure (lessons 3, 4 and 12).
• Physics, nuclear and radioactivity: exponential decay, the decay constant and half-life (lessons 5 and 6).
• Physics, quantum and waves: photon energy and spectra (lesson 8).
• Chemistry, atomic structure: time-of-flight mass spectrometry and relative isotopic mass (lesson 7).
• Chemistry, organic: amino acids, optical isomerism and chirality (lesson 11).
• Chemistry, bonding: metallic bonding and alloys, extended to the crystal structures of iron–nickel metal, which go beyond A-level (lesson 10).
• Geology: igneous petrology, partial melting, fractional crystallisation, mineral identification, metamorphism and impact processes (lessons 9 and 12).
• Maths: logarithms and exponentials, standard form, rearranging equations, uncertainties and graphs throughout.

Each lesson has learning goals, a short activity and a five-question quiz. Finish every quiz to unlock the printable certificate. Your progress is saved on this device only.