https://www.khanacademy.org/college-careers-more/bjc/2015-challenge/2015-physics/v/bjc-antimatter 2020-11-18T19:37:54Z Antimatter By Parker Ruth “Antimatter is a weird topsy-turvy shadow of matter, like tweedledum to our tweedledee, where left becomes right and positive turns into negative.” When I first read these words from Frank Close’s book​ Antimatter, I was captivated by the idea that science can be just as mind bending as science fiction — only real!  video https://cdn.kastatic.org/googleusercontent/HtnGiCJPbJROifpHNW3GFpCwP4LTUfiCoOyBx1GUIgbYzqILQKbrYk0o8Mszny8os_e-kW76yqQ3WEl06ltEPZY Antimatter By Parker Ruth “Antimatter is a weird topsy-turvy shadow of matter, like tweedledum to our tweedledee, where left becomes right and positive turns into negative.” When I first read these words from Frank Close’s book​ Antimatter, I was captivated by the idea that science can be just as mind bending as science fiction — only real!  https://cdn.kastatic.org/ka-youtube-converted/Vi0bkfqLkpU.mp4/Vi0bkfqLkpU.mp4 596 Antiparticles, neutrinos and energy characteristics of nuclear radiations https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:radioactive-decay/v/beta-decay 2024-06-13T01:38:36.313442654Z Beta decay During beta minus decay, a neutron in an unstable nucleus transforms into a proton, releasing a high energy electron and antineutrino in the process. During beta plus decay, a proton in an unstable nucleus transforms into a neutron, releasing a high energy positron and neutrino in the process. Beta particles carry away energy lost by the nucleus and are ionizing radiation. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/ba743322-3e33-4a0c-9f5c-684e6ef36846_1280_720_base.png Beta decay During beta minus decay, a neutron in an unstable nucleus transforms into a proton, releasing a high energy electron and antineutrino in the process. During beta plus decay, a proton in an unstable nucleus transforms into a neutron, releasing a high energy positron and neutrino in the process. Beta particles carry away energy lost by the nucleus and are ionizing radiation. https://cdn.kastatic.org/ka-youtube-converted/iGr6atucsBw.mp4/iGr6atucsBw.mp4 708 Antiparticles, neutrinos and energy characteristics of nuclear radiations https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:radioactive-decay/e/apply-beta-decay 2026-03-26T05:20:35.16058035Z Apply: beta decay Apply your understanding of beta decay in this set of free practice questions. Allen Ruch exercise https://www.khanacademy.org/science/grade-11-physics-snc-aligned/x1d0fed5276339e80:relativity-and-particle-physics/x1d0fed5276339e80:antiparticles-neutrinos-and-energy-characteristics-of-nuclear-radiations/a/decay-graphs-and-half-lives-article 2021-05-25T21:59:57Z Decay graphs and half lives article article https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:radioactive-decay/v/intro-to-radioactive-decay 2024-06-13T01:38:36.313442654Z Intro to radioactive decay During radioactive decay, an unstable nucleus (the "parent") spontaneously changes to become a different nucleus (the "daughter"), emitting radiation in the process. The nuclear radiation emitted during radioactive decay is high energy, ionizing radiation. Nuclear radiation is potentially dangerous to living things but also has many beneficial applications. Types of radioactive decay include alpha, beta, and gamma. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/fc1e7aaf-5503-47a4-b1d8-a455ec7baf56_1280_720_base.png Intro to radioactive decay During radioactive decay, an unstable nucleus (the "parent") spontaneously changes to become a different nucleus (the "daughter"), emitting radiation in the process. The nuclear radiation emitted during radioactive decay is high energy, ionizing radiation. Nuclear radiation is potentially dangerous to living things but also has many beneficial applications. Types of radioactive decay include alpha, beta, and gamma. https://cdn.kastatic.org/ka-youtube-converted/P_SD5Rt6XMk.mp4/P_SD5Rt6XMk.mp4 482 Antiparticles, neutrinos and energy characteristics of nuclear radiations https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:radioactive-decay/e/understand-radioactive-decay 2025-05-15T18:29:02.3376193Z Understand: radioactive decay Check your understanding of radioactive decay in this set of free practice questions. Allen Ruch exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:radioactive-decay/v/alpha-decay 2024-06-13T01:38:36.313442654Z Alpha decay During alpha decay, a large, unstable parent nucleus becomes a smaller daughter nucleus. It does this by emitting an alpha particle, a clump of two protons and two neutrons (a He-4 nucleus). The nucleus's atomic number decreases by two, and its mass number decreases by four. The alpha particle is high-energy ionizing radiation—it travels at high speed because it carries away the majority of the energy lost by the nucleus during the decay. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/7136219a-e568-4b4b-86a8-619b38b94719_1280_720_base.png Alpha decay During alpha decay, a large, unstable parent nucleus becomes a smaller daughter nucleus. It does this by emitting an alpha particle, a clump of two protons and two neutrons (a He-4 nucleus). The nucleus's atomic number decreases by two, and its mass number decreases by four. The alpha particle is high-energy ionizing radiation—it travels at high speed because it carries away the majority of the energy lost by the nucleus during the decay. https://cdn.kastatic.org/ka-youtube-converted/QCZQCi_uKpM.mp4/QCZQCi_uKpM.mp4 666 Antiparticles, neutrinos and energy characteristics of nuclear radiations https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:radioactive-decay/e/apply-alpha-decay 2026-03-26T05:20:35.16058035Z Apply: alpha decay Apply your understanding of alpha decay in this set of free practice questions. Allen Ruch exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:radioactive-decay/v/gamma-decay 2024-06-13T01:38:36.313442654Z Gamma decay During gamma decay, an excited nucleus releases energy in the form of a gamma photon. Gamma radiation is high-energy electromagnetic radiation (light) which has a shorter wavelength and higher frequency than visible light. Gamma rays are ionizing radiation. The number of protons and neutrons in the parent nucleus does not change, so the identity of the daughter nucleus is the same as the parent, but in a lower energy state. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/fdf6f6e7-aa8f-4691-8394-6d340a7a1a4a_1280_720_base.png Gamma decay During gamma decay, an excited nucleus releases energy in the form of a gamma photon. Gamma radiation is high-energy electromagnetic radiation (light) which has a shorter wavelength and higher frequency than visible light. Gamma rays are ionizing radiation. The number of protons and neutrons in the parent nucleus does not change, so the identity of the daughter nucleus is the same as the parent, but in a lower energy state. https://cdn.kastatic.org/ka-youtube-converted/ksLNmLQbNT4.mp4/ksLNmLQbNT4.mp4 709 Antiparticles, neutrinos and energy characteristics of nuclear radiations https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:nuclear-chemistry-hs/x2613d8165d88df5e:radioactive-decay/e/apply-alpha-beta-gamma 2026-03-26T05:20:35.16058035Z Apply: alpha, beta, and gamma decay Apply your understanding of alpha, beta, and gamma decay in this set of free practice questions. Allen Ruch exercise