half-life
Radioactive decay measure
Half-life is the time required for half of something to decay, transform, or disappear.
In physics, it measures radioactive decay: Carbon-14 has a half-life of about 5,700 years.
The term extends to anything that diminishes over time—the half-life of a drug in the bloodstream, the half-life of a celebrity's fame, the half-life of outrage on social media. (Capitalized Half-Life is the video game series.)
Emitting nuclear decay particles
- isotopeElemental variant by mass
- uraniumElement ninety-two
- plutoniumActinide, atomic number 94
- thoriumActinide, atomic number ninety
radiation · fission · alpha · beta · gamma · neutrons · transmutation · disintegration
Increasing by constant ratio
- logarithmicBased on exponents
- calculusMathematical analysis system
- asymptoteUnreached bounding curve
- inverseOpposite in position
Act of removing entirely
- clearancePermitted passage or approval
- metabolismCellular nutrient conversion
- bioavailabilityFraction reaching active circulation
- pharmacokineticsDrug fate in body
absorption · distribution · excretion · cytochrome · liver · enzymes · biotransformation · detoxification
Radioactive isotope for dating
- radiocarbonDecaying carbon isotope
- archaeologyStudy of physical remnants
- paleontologyStudy of ancient organisms
- geochronologyStudy of geological ages
fossil · stratigraphy · sediment · rock · mineral · paleoclimatology · paleobotany · paleoecology
Medicinal radioactive substance
- radiolabelingAttaching radioactive tracers to molecules
- SPECTGamma-emitting radiotracer imaging method
- technetiumFirst artificially produced element
- diagnosticTest to identify problems
imaging · contrast · injection · uptake · biodistribution
Same formula, different shape
- excitationStimulation of response
- gamma-rayHighest-energy electromagnetic wave
- transitionChange from one state
- technetium-99mMetastable medical radioisotope
radioactive
Emitting nuclear decay particles
thorium · radiation · fission · alpha · beta · gamma · neutrons · transmutation · disintegration · dosimeter
exponential
Increasing by constant ratio
- logarithmicBased on exponents
- calculusMathematical analysis system
- asymptoteUnreached bounding curve
inverse · formula · equation · probability
elimination
Act of removing entirely
- clearancePermitted passage or approval
- metabolismCellular nutrient conversion
- bioavailabilityFraction reaching active circulation
pharmacokinetics · absorption · distribution · excretion · cytochrome · liver · enzymes · biotransformation · detoxification · metabolites
carbon-14
Radioactive isotope for dating
- radiocarbonDecaying carbon isotope
- archaeologyStudy of physical remnants
- paleontologyStudy of ancient organisms
geochronology · fossil · stratigraphy · sediment · rock · mineral · paleoclimatology · paleobotany · paleoecology · fractionation
radiopharmaceutical
Medicinal radioactive substance
- radiolabelingAttaching radioactive tracers to molecules
- SPECTGamma-emitting radiotracer imaging method
- technetiumFirst artificially produced element
diagnostic · imaging · contrast · injection · uptake · biodistribution
isomer
Same formula, different shape
- excitationStimulation of response
- gamma-rayHighest-energy electromagnetic wave
- transitionChange from one state
- geochemistryisotope geochemistry, biogeochemistry, trace element, trace elements, isotopes
- particle physicsquark, quarks, lepton, leptons, boson
- radiobiologyradiobiology, DNA damage, mutations, ionizing radiation, cell damage
- beta decaybeta particle, beta radiation, electron emission, antineutrino, neutrino
- Carbon Datingradiocarbon, isotope, decay rate
- Chemical Theoryatomic theory, molecular theory, kinetic theory, quantum theory, ligand field theory
half-lifepermanence
Quality of lasting indefinitely
eternity · stability · immortality · perpetuity · everlasting
half-lifestability
Resistance to displacement
inertness · permanence · unchanging · immutable · steady state