https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:thermochemistry/x2613d8165d88df5e:thermal-energy-and-equilibrium/v/thermal-energy-temperature-and-heat 2024-06-15T21:30:38.850830378Z Thermal energy, temperature, and heat Thermal energy refers to the kinetic energy of randomly moving particles in a substance. Particles can have translational, rotational, and/or vibrational kinetic energy, depending on the state of matter. Temperature is a measure of the average kinetic energy of the particles in a substance. Heat is thermal energy that transfers into or out of a system. Heat can transfer by conduction, convection, or radiation. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/da734486-a3ad-441b-b84e-bc7e7136cc17_1280_720_base.png Thermal energy, temperature, and heat Thermal energy refers to the kinetic energy of randomly moving particles in a substance. Particles can have translational, rotational, and/or vibrational kinetic energy, depending on the state of matter. Temperature is a measure of the average kinetic energy of the particles in a substance. Heat is thermal energy that transfers into or out of a system. Heat can transfer by conduction, convection, or radiation. https://cdn.kastatic.org/ka-youtube-converted/-7Gl-yKF6Y4.mp4/-7Gl-yKF6Y4.mp4 692 Thermal energy https://www.khanacademy.org/science/ms-chemistry/xc370bc422b7f75fc:physical-properties-of-matter/xc370bc422b7f75fc:intrinsic-and-extrinsic-properties/a/temperature 2026-04-28T11:10:43.64230357Z Learn and try: Temperature Learn about temperature as a measure of average kinetic energy and how to read and use the Celsius scale in scientific measurements. Discover how a thermometer works and how different temperature scales were developed. article https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:thermochemistry/x2613d8165d88df5e:thermal-energy-and-equilibrium/v/first-and-second-laws-of-thermodynamics 2024-06-15T21:30:38.850830378Z First and second laws of thermodynamics The first law of thermodynamics states that if a system gains/loses some amount of energy, the surroundings must lose/gain the same amount of energy. The second law of thermodynamics states that entropy does not spontaneously decrease. Entropy is a measure of how spread out energy is. As an example, if two systems at different temperatures are in contact, heat will flow from the warmer system to the cooler system until they reach thermal equilibrium (equal temperatures). Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/95561fa4-d391-4be8-bcd2-b2a41f597102_1280_720_base.png First and second laws of thermodynamics The first law of thermodynamics states that if a system gains/loses some amount of energy, the surroundings must lose/gain the same amount of energy. The second law of thermodynamics states that entropy does not spontaneously decrease. Entropy is a measure of how spread out energy is. As an example, if two systems at different temperatures are in contact, heat will flow from the warmer system to the cooler system until they reach thermal equilibrium (equal temperatures). https://cdn.kastatic.org/ka-youtube-converted/f1OokOgtcqg.mp4/f1OokOgtcqg.mp4 740 Thermal energy https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:thermochemistry/x2613d8165d88df5e:thermal-energy-and-equilibrium/e/understand-thermal-energy-and-equilibrium 2026-06-30T16:30:41.535282189Z Understand: Thermal energy and equilibrium Check your understanding of thermal energy and thermal equilibrium in this set of free, standards-aligned practice questions. Allen Ruch exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:thermochemistry/x2613d8165d88df5e:thermal-energy-and-equilibrium/e/apply-thermal-energy-and-equilibrium 2026-06-30T16:30:41.535282189Z Apply: Thermal energy and equilibrium Apply your understanding of thermal energy and thermal equilibrium in this set of free, standards-aligned practice questions. Allen Ruch exercise