https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/v/earths-place-in-the-universe 2024-01-04T21:44:22.995765104Z Earth's place in the universe Humans have used models to understand Earth's place in the universe. The geocentric model, placing Earth at the center, was replaced by the heliocentric model, with the sun at the center. This change better explains the movement of celestial bodies and shows that Earth's rotation causes the sun's apparent motion. Khan Academy video https://cdn.kastatic.org/ka_thumbnails_cache/367f5f88-2954-4708-a8a2-1ea2aa569771_1280_720_base.png Earth's place in the universe Humans have used models to understand Earth's place in the universe. The geocentric model, placing Earth at the center, was replaced by the heliocentric model, with the sun at the center. This change better explains the movement of celestial bodies and shows that Earth's rotation causes the sun's apparent motion. https://cdn.kastatic.org/ka-youtube-converted/Pv0Re0YEEq0.mp4/Pv0Re0YEEq0.mp4 294 The Earth https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/a/the-geocentric-universe 2021-04-29T07:58:59Z The geocentric universe article https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/a/the-heliocentric-model 2021-04-29T07:51:13Z The heliocentric model article https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/a/earths-place-in-the-universe 2026-04-29T10:50:35.589391704Z Key points: Earth’s place in the universe Review your understanding of Earth's place in the universe in this free article aligned to NGSS standards. article https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/e/understand-earths-place-in-the-universe 2026-03-11T01:50:44.937458787Z Understand: Earth's place in the universe Check your understanding of Earth's place in the universe in this set of free practice questions aligned to NGSS standards. Lauren Rosebrugh exercise https://www.khanacademy.org/science/cosmology-and-astronomy/earth-history-topic/earth-title-topic/v/seasons-aren-t-dictated-by-closeness-to-sun 2021-04-12T12:34:14Z Seasons aren't dictated by closeness to sun Why our closeness to the sun does not dictate the seasons Sal Khan video https://cdn.kastatic.org/googleusercontent/O5RJ-uooWimBhoFHzHsdrNiIZSukWb9kjzCZUsL2bMGGcLwnq7paVTg4IZms9XkAQi8QlAiayksyGBHHdxxoWQNHyQ Seasons aren't dictated by closeness to sun Why our closeness to the sun does not dictate the seasons https://cdn.kastatic.org/ka-youtube-converted/SJUd5du0T08.mp4/SJUd5du0T08.mp4 279 The Earth https://www.khanacademy.org/science/cosmology-and-astronomy/earth-history-topic/earth-title-topic/v/how-earth-s-tilt-causes-seasons 2021-04-29T19:30:40Z How Earth's tilt causes seasons How Earth's tilt causes seasons Sal Khan video https://cdn.kastatic.org/googleusercontent/K9UXKCl1RzBx4ixuOkDXjrhe8iZ8yKCR-RohCF4pp551J6nqA8I7f4R6zUG9JPU13oR2KUF46T8ppVSd0ZLch0DK How Earth's tilt causes seasons How Earth's tilt causes seasons https://cdn.kastatic.org/ka-youtube-converted/05qDIjKevJo.mp4/05qDIjKevJo.mp4 1247 The Earth https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/e/understand-seasons 2026-04-26T16:30:39.382257956Z Understand: Seasons Check your understanding of seasons in this set of free practice questions aligned to NGSS standards. Khan Academy exercise https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/e/revolution-of-earth 2026-04-07T23:17:37.123726494Z Revolution of Earth Explore Grade 7 Science exercise on Revolution of the Earth. Learn how Earth’s yearly orbit causes seasons, solstices, equinoxes, day–night variations, and changing constellations, while correcting common misconceptions. Yajurva Joshi exercise https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/e/rotation-of-earth 2026-04-08T00:54:09.631945657Z Rotation of Earth Engage with this interactive Grade 7 Science exercise on Rotation of the Earth. Explore why the Sun, Moon, and stars appear to move, understand the day-night cycle, and correct common misconceptions with creative question formats. Yajurva Joshi exercise https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/v/phases-of-the-moon 2022-09-02T07:28:17.303436145Z Phases of the moon A moon phase is the shape of moon's sunlit portion as seen from Earth. There are a total of eight moon phases: new, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, third quarter, and waning crescent. These phases repeat every 29.5 days. Khan Academy video https://cdn.kastatic.org/ka_thumbnails_cache/b33175fe-10b7-4f4f-91da-d8c1d61bb849_1280_720_base.png Phases of the moon A moon phase is the shape of moon's sunlit portion as seen from Earth. There are a total of eight moon phases: new, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, third quarter, and waning crescent. These phases repeat every 29.5 days. https://cdn.kastatic.org/ka-youtube-converted/f592IgRzq2E.mp4/f592IgRzq2E.mp4 254 The Earth https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/a/the-moon-and-its-motions 2026-04-30T07:30:36.209464894Z Key points: The moon and its motions Review your understanding of the moon and its motions in this free article aligned to NGSS standards. article https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/e/understand-the-moon-and-its-motions 2026-04-30T07:30:36.209464894Z Understand: The moon and its motions Check your understanding of the moon and its motions in this set of free practice questions aligned to NGSS standards. Lauren Rosebrugh exercise https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/e/apply-the-moon-and-its-motions 2026-04-30T07:30:36.209464894Z Apply: The moon and its motions Apply your understanding of the moon and its motions in this set of free practice questions aligned to NGSS standards. Lauren Rosebrugh exercise https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/v/why-earth-is-unique-earth 2026-04-30T07:30:36.209464894Z Why Earth is unique - Earth Why Earth is unique Khan Academy Pakistan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Why Earth is unique - Earth Why Earth is unique https://cdn.kastatic.org/ka-youtube-converted/urUDy2Hj07k.mp4/urUDy2Hj07k.mp4 396 The Earth https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/v/earthsmagnetic 2020-06-23T07:22:41Z Earth's magnetic shield Magnets do more than pick up metal objects and attract iron filings. In fact, without the strong magnetic field Earth projects into space, life as we know it might not exist. Find out how it works… NOVA video https://cdn.kastatic.org/googleusercontent/XsGOfQtxYVmo9-S04RnHa4Vu4jv-O3hulctmoMinTqqOgyNdP_xpAbG6e-5hRHX4b-MdfwNMK4A2cFIkBwRHb0Sv Earth's magnetic shield Magnets do more than pick up metal objects and attract iron filings. In fact, without the strong magnetic field Earth projects into space, life as we know it might not exist. Find out how it works… https://cdn.kastatic.org/ka-youtube-converted/URN-XyZD2vQ.mp4/URN-XyZD2vQ.mp4 126 The Earth https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:space-science/x0e04e0cb682fb793:the-earth/e/earth-s-magnetic-shield-quiz 2021-06-05T02:06:19Z Earth's magnetic shield quiz Try this quiz about Earth's magnetic shield. NOVA exercise