https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:half-life-and-radiometric-dating/v/half-life-radiometric-dating 2024-06-13T01:38:36.313442654Z Half-life Half-life is the time required for half of a radioactive sample to decay. Half-life cannot be changed—nuclei cannot be forced to decay faster or slower. Additionally, we cannot predict when an individual nucleus will decay. However, when analyzing a large sample containing many nuclei, half-life allows us to predict how much of the sample will remain after a given amount of time. This is useful for radiometric dating. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/deeccc60-0655-4091-9ae6-6ed1ffa8ba4f_1280_720_base.png Half-life Half-life is the time required for half of a radioactive sample to decay. Half-life cannot be changed—nuclei cannot be forced to decay faster or slower. Additionally, we cannot predict when an individual nucleus will decay. However, when analyzing a large sample containing many nuclei, half-life allows us to predict how much of the sample will remain after a given amount of time. This is useful for radiometric dating. https://cdn.kastatic.org/ka-youtube-converted/gDpyBifg6-s.mp4/gDpyBifg6-s.mp4 656 Half Life https://www.khanacademy.org/science/ap-physics-2/x0e2f5a2c:modern-physics/x0e2f5a2c:nuclear-physics/v/half-life-of-radioactive-isotopes 2021-01-04T18:35:18Z Half-life plot Definition of half-life and graphing the decay of phosphorus-32. Calculating how much phosphorus-32 remains after 57.2 days.  Jay video https://cdn.kastatic.org/googleusercontent/HPQHj-3fTxXSq1B7wgA7u-e8wXGvEiC7zVPi62FvpcD_onIE1kTwxpX4Es4YQ197WIv6htItx8aiyHNpxWfhLZtb Half-life plot Definition of half-life and graphing the decay of phosphorus-32. Calculating how much phosphorus-32 remains after 57.2 days.  https://cdn.kastatic.org/ka-youtube-converted/dnYyMHSSb8M.mp4/dnYyMHSSb8M.mp4 407 Half Life https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:half-life-and-radiometric-dating/e/understand-half-life-and-radiometric-dating 2026-05-03T15:00:46.862745588Z Understand: Half-life and radiometric dating Check your understanding of half-life and radiometric dating in this set of free practice questions. Allen Ruch exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:half-life-and-radiometric-dating/e/apply-half-life-and-radiometric-dating 2026-05-03T15:00:46.862745588Z Apply: Half-life and radiometric dating Apply your understanding of half-life and radiometric dating in this set of free practice questions. Allen Ruch exercise https://www.khanacademy.org/math/engageny-precalc/precalc-3/precalc-3c-exp-lop/v/half-life 2021-01-04T18:35:20Z Half-life and carbon dating Carbon dating is a real-life example of a first-order reaction. This video explains half-life in the context of radioactive decay. Sal Khan video https://cdn.kastatic.org/googleusercontent/A1D3qsWagCLFTIIalI5f9lmbc2WgRuxZeHl7C4SaFx0cdCEbZs0ZTrEKIa3N0mypb92VTDNba1yBfX-fXn8C6lg Half-life and carbon dating Carbon dating is a real-life example of a first-order reaction. This video explains half-life in the context of radioactive decay. https://cdn.kastatic.org/ka-youtube-converted/9REPnibO4IQ.mp4/9REPnibO4IQ.mp4 751 Half Life https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:nuclear-physics/x0e04e0cb682fb793:half-life/e/half-life 2026-04-07T23:17:37.123726494Z Half-life (qualitative) Let's solve some problems to better understand the meaning of the term half-life. And remove some possible misconceptions around the same. Aakash exercise https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:nuclear-physics/x0e04e0cb682fb793:half-life/e/half-life-intermediate 2026-04-08T01:19:59.083532605Z Half life (intermediate) Let's practice some problems to understand better the formulas that help us find the half-life of a radioactive sample and other related quantities. Satra exercise https://www.khanacademy.org/science/ap-biology/natural-selection/evidence-for-evolution-ap/v/carbon-14-dating-1 2023-08-07T17:09:37.131449861Z Carbon 14 dating 1 Carbon-14 forms in the atmosphere through cosmic rays interacting with nitrogen-14, creating a small fraction of carbon-14 in living organisms. When an organism dies, its carbon-14 decays back into nitrogen-14 at a known rate, called a half-life (5,730 years). By measuring the remaining carbon-14 in fossils, scientists can estimate their age, helping us understand the history of life on Earth. Sal Khan video https://cdn.kastatic.org/googleusercontent/mPZoGtLX4UzhlYgN7HPDXacSfr7TM7Aeb32qIM-ZLq4Kd1OSbizg203sheTJuON9lPx8XyjRMIRoXRqOKU83yHs Carbon 14 dating 1 Carbon-14 forms in the atmosphere through cosmic rays interacting with nitrogen-14, creating a small fraction of carbon-14 in living organisms. When an organism dies, its carbon-14 decays back into nitrogen-14 at a known rate, called a half-life (5,730 years). By measuring the remaining carbon-14 in fossils, scientists can estimate their age, helping us understand the history of life on Earth. https://cdn.kastatic.org/ka-youtube-converted/8wYvKeSK1IY.mp4/8wYvKeSK1IY.mp4 603 Half Life https://www.khanacademy.org/science/biology/history-of-life-on-earth/radiometric-dating/v/carbon-14-dating-2 2020-08-28T13:57:04Z Carbon 14 dating 2 Carbon 14 Dating 2 Sal Khan video https://cdn.kastatic.org/googleusercontent/r54m14ppocGPS9XS0Uh_zYCiXTmBBN7hIGs432HflBuG-Kd8oEcqXwkPpSThY3Yb1yQk0-2e1bz0DwlBL0ukpsHO Carbon 14 dating 2 Carbon 14 Dating 2 https://cdn.kastatic.org/ka-youtube-converted/4YUtnod-YuE.mp4/4YUtnod-YuE.mp4 255 Half Life https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:nuclear-physics/x0e04e0cb682fb793:half-life/v/fossil-dating-heredity-and-evolution 2026-05-11T04:40:42.021307954Z Fossil dating Fossil dating Heredity & Evolution Khan Academy Pakistan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Fossil dating Fossil dating Heredity & Evolution https://cdn.kastatic.org/ka-youtube-converted/qSVcp9jv3sk.mp4/qSVcp9jv3sk.mp4 555 Half Life