- observation
- observations are trimmed with theoretical shears
- observer effect
- occult
- Ockham's Razor
- octet rule
- octet rule framework
- On the Magnet
- On the Origin of Species
- one conservation law swallowed others
- ontological commitments
- ontology
- open questions
- optical mining sweats water from asteroids and comets
- optimally guided instruction
- optimum level of simplification
- ORCID
- ores develop from seed like an embryo in the womb
- outer shell of carbon atom will always be looking for two oxygens to complete itself
- oxygen jumps onto hydrogen and carbon
- oxygen likes to combine with things