{"page":"\u003clink rel=\"stylesheet\" href=\"https://lessonplanet.com/assets/packs/css/resources-c03aa079.css\" /\u003e\n\u003clink rel=\"stylesheet\" href=\"https://lessonplanet.com/assets/packs/css/lp_boclips_stylesheets-517835be.css\" media=\"all\" /\u003e\n\u003cdiv data-title='Why Are There \u0026#39;24\u0026#39; Hours In A Day?' data-url='/boclips/videos/67487b6a71799213ef3e3cd1' data-video-url='/boclips/videos/67487b6a71799213ef3e3cd1' id='bo_player_modal'\u003e\n\u003cdiv class='boclips-resource-page modal-dialog panel-container'\u003e\n\u003cdiv class='react-notifications-root'\u003e\u003c/div\u003e\n\u003cdiv class='rp-header'\u003e\n\u003cdiv class='rp-type'\u003e\n\u003ci aria-hidden='true' class='fai fa-regular fa-circle-play'\u003e\u003c/i\u003e\nVideo\n\u003c/div\u003e\n\u003ch1 class='rp-title' id='video-title'\u003e\nWhy Are There \u0026#39;24\u0026#39; Hours In A Day?\n\u003c/h1\u003e\n\u003cdiv class='rp-actions'\u003e\n\u003cdiv class='mr-1'\u003e\n\u003ca class=\"btn btn-success\" data-posthog-event=\"Signup: LP Signup Activity\" data-posthog-location=\"body_link_boclips\" data-remote=\"true\" href=\"/subscription/new\"\u003e\u003cspan\u003e\u003cspan\u003eGet Free Access\u003c/span\u003e\u003cspan class=\"\"\u003e for 10 Days\u003c/span\u003e\u003cspan\u003e!\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class='rp-body'\u003e\n\u003cdiv class='rp-info'\u003e\n\u003cdiv aria-label='Hide resource details' class='rp-hide-info' role='button' tabindex='0'\u003e\u0026times;\u003c/div\u003e\n\u003ci aria-label='Expand resource details' class='rp-expand-info fai fa-solid fa-up-right-and-down-left-from-center' role='button' tabindex='0'\u003e\u003c/i\u003e\n\u003ci aria-label='Compress resource details' class='rp-compress-info fai fa-solid fa-down-left-and-up-right-to-center' role='button' tabindex='0'\u003e\u003c/i\u003e\n\u003cdiv class='rp-rating'\u003e\n\u003cspan class='resource-pool'\u003e\n\u003cspan class='pool-label'\u003ePublisher:\u003c/span\u003e\n\u003cspan class='pool-name'\u003e\n\u003cspan class='text'\u003e\u003ca data-publisher-id=\"30359304\" href=\"/search?publisher_ids%5B%5D=30359304\"\u003eScience ABC\u003c/a\u003e\u003c/span\u003e\n\u003c/span\u003e\n\u003c/span\u003e\n\u003c/div\u003e\n\u003cdiv class='rp-description'\u003e\n\u003cspan class='short-description'\u003eThe 24-hour day concept comes from the ancient Egyptians. They divided the day into 10 hours with devices like shadow clocks and then added one hour at each end (one for twilight and one at the end of the day). Later, a T-shaped bar was...\u003c/span\u003e\n\u003cspan class='full-description hide'\u003eThe 24-hour day concept comes from the ancient Egyptians. They divided the day into 10 hours with devices like shadow clocks and then added one hour at each end (one for twilight and one at the end of the day). Later, a T-shaped bar was made by Egyptians, which was calibrated to divide the time between sunrise and sunset into 12 parts. The absence of sunlight made it difficult to divide the time at night. Its pretty interesting to learn how they managed to do this. The nighttime division of time was based on the observation of stars. In those ancient times, with no sophisticated technology to use, they instead chose 36 star groups (small constellations) called decans, which rose consecutively on the horizon as the earth rotated. Each decan rose before sunrise and marked the beginning of a 10-day period. A total of 36 decans thus led to 36*10=360 days of a year. From one twilight to another, 18 of these decans were visible. However, each twilight period had 3 of these decans assigned, leaving 12 for the period of complete darkness. Thus, the rise of each decan marked an hour, so we ended up with 12 hours in each night. Then, Hipparchus gave us the Equinoctial hours by proposing the division of a day into 24 equal hours.\u003c/span\u003e\n\u003c/div\u003e\n\u003cdiv class='action-container flex justify-between'\u003e\n\u003cbutton aria-expanded='false' aria-label='Read more description' class='rp-full-description' type='button'\u003e\n\u003ci class='fai fa-solid fa-align-left'\u003e\u003c/i\u003e\n\u003cspan id='read_more'\u003eRead More\u003c/span\u003e\n\u003c/button\u003e\n\u003cdiv class='rp-report'\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv aria-labelledby='resource-details-heading' class='rp-info-section'\u003e\n\u003ch2 class='title' id='resource-details-heading'\u003eResource Details\u003c/h2\u003e\n\u003cdiv class='rp-resource-details clearfix'\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt\u003eCurator Rating\u003c/dt\u003e\n\u003cdd\u003e\u003cspan class=\"star-rating\" aria-label=\"4.0 out of 5 stars\" role=\"img\"\u003e\u003ci class=\"fa-solid fa-star text-action\" aria-hidden=\"true\"\u003e\u003c/i\u003e\u003ci class=\"fa-solid fa-star text-action\" aria-hidden=\"true\"\u003e\u003c/i\u003e\u003ci class=\"fa-solid fa-star text-action\" aria-hidden=\"true\"\u003e\u003c/i\u003e\u003ci class=\"fa-solid fa-star text-action\" aria-hidden=\"true\"\u003e\u003c/i\u003e\u003ci class=\"fa-regular fa-star text-action\" aria-hidden=\"true\"\u003e\u003c/i\u003e\u003c/span\u003e\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt class=\"educator-rating-title\"\u003eEducator Rating\u003c/dt\u003e\u003cdd\u003e\u003cdiv class=\"educator-rating-details\" data-path=\"/educator_ratings/rrp_data?resourceable_id=87259026\u0026amp;resourceable_type=Boclips%3A%3AVideoMetadata\"\u003e\u003cspan class=\"not-yet-rated\"\u003eNot yet Rated\u003c/span\u003e\u003c/div\u003e\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt\u003eMedia Length\u003c/dt\u003e\n\u003cdd\u003e3:26\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt\u003eGrade\u003c/dt\u003e\u003cdd title=\"Grade\"\u003ePre-K - Higher Ed\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt\u003eSubjects\u003c/dt\u003e\u003cdd\u003e\u003cspan\u003e\u003ca href=\"/search?grade_ids%5B%5D=260\u0026amp;grade_ids%5B%5D=261\u0026amp;grade_ids%5B%5D=247\u0026amp;grade_ids%5B%5D=248\u0026amp;grade_ids%5B%5D=249\u0026amp;grade_ids%5B%5D=250\u0026amp;grade_ids%5B%5D=251\u0026amp;grade_ids%5B%5D=252\u0026amp;grade_ids%5B%5D=253\u0026amp;grade_ids%5B%5D=254\u0026amp;grade_ids%5B%5D=255\u0026amp;grade_ids%5B%5D=256\u0026amp;grade_ids%5B%5D=257\u0026amp;grade_ids%5B%5D=258\u0026amp;grade_ids%5B%5D=259\u0026amp;search_tab_id=1\u0026amp;subject_ids%5B%5D=365221\"\u003eScience\u003c/a\u003e\u003c/span\u003e\u003c/dd\u003e\u003cdd class=\"text-muted\"\u003e\u003ci class=\"fa-solid fa-lock mr5\"\u003e\u003c/i\u003e6 more...\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt\u003eMedia Type\u003c/dt\u003e\u003cdd\u003e\u003cspan\u003e\u003ca href=\"/search?grade_ids%5B%5D=260\u0026amp;grade_ids%5B%5D=261\u0026amp;grade_ids%5B%5D=247\u0026amp;grade_ids%5B%5D=248\u0026amp;grade_ids%5B%5D=249\u0026amp;grade_ids%5B%5D=250\u0026amp;grade_ids%5B%5D=251\u0026amp;grade_ids%5B%5D=252\u0026amp;grade_ids%5B%5D=253\u0026amp;grade_ids%5B%5D=254\u0026amp;grade_ids%5B%5D=255\u0026amp;grade_ids%5B%5D=256\u0026amp;grade_ids%5B%5D=257\u0026amp;grade_ids%5B%5D=258\u0026amp;grade_ids%5B%5D=259\u0026amp;search_tab_id=2\u0026amp;type_ids%5B%5D=4543647\"\u003eInstructional Videos\u003c/a\u003e\u003c/span\u003e\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt\u003eSource:\u003c/dt\u003e\n\u003cdiv class='preview-source' data-animation='true' data-boundary='.rp-info' data-container='.rp-resource-details' data-html='false' data-title='Science gets a bad rep as being boring, difficult and for very smart and boring people (see: nerds). But that doesn\u0026#39;t have to be the case. At ScienceABC we believe that if science is communicated simply and made relatable and fun, it can be for everyone. As Micheal Jackson said best, \u0026quot;as simple as ABC.\u0026quot;' data-trigger='hover focus'\u003e\n\u003cspan\u003eScienceABC\u003c/span\u003e\n\u003ci aria-hidden='true' class='fa-solid fa-circle-info channel-tooltip-icon' id='channel-tooltip'\u003e\u003c/i\u003e\n\u003c/div\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt\u003eDate\u003c/dt\u003e\n\u003cdd\u003e2022\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003ci aria-hidden='true' class='fai fa-solid fa-language'\u003e\u003c/i\u003e\n\u003cdt\u003eLanguage\u003c/dt\u003e\u003cdd\u003eEnglish\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt\u003eAudiences\u003c/dt\u003e\u003cdd\u003e\u003cspan\u003e\u003ca href=\"/search?audience_ids%5B%5D=371079\u0026amp;grade_ids%5B%5D=260\u0026amp;grade_ids%5B%5D=261\u0026amp;grade_ids%5B%5D=247\u0026amp;grade_ids%5B%5D=248\u0026amp;grade_ids%5B%5D=249\u0026amp;grade_ids%5B%5D=250\u0026amp;grade_ids%5B%5D=251\u0026amp;grade_ids%5B%5D=252\u0026amp;grade_ids%5B%5D=253\u0026amp;grade_ids%5B%5D=254\u0026amp;grade_ids%5B%5D=255\u0026amp;grade_ids%5B%5D=256\u0026amp;grade_ids%5B%5D=257\u0026amp;grade_ids%5B%5D=258\u0026amp;grade_ids%5B%5D=259\u0026amp;search_tab_id=1\"\u003eFor Teacher Use\u003c/a\u003e\u003c/span\u003e\u003c/dd\u003e\u003cdd class=\"text-muted\"\u003e\u003ci class=\"fa-solid fa-lock mr5\"\u003e\u003c/i\u003e2 more...\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cdiv class='detail'\u003e\n\u003cdl\u003e\n\u003cdt\u003eUsage Permissions\u003c/dt\u003e\u003cdd\u003eFine Print: Educational Use\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv aria-labelledby='additional-materials-heading' class='rp-info-section'\u003e\n\u003ch2 class='title' id='additional-materials-heading'\u003eAdditional Materials\u003c/h2\u003e\n\u003cdiv class='additional-material'\u003e\n\u003ci aria-hidden='true' class='fai fa-solid fa-lock'\u003e\u003c/i\u003e\n\u003ca class=\"text-muted\" title=\"Video Transcript\" data-html=\"true\" data-placement=\"bottom\" data-trigger=\"click\" data-content=\"\u003cdiv class=\u0026quot;text-center py-2\u0026quot;\u003e\u003ca class=\u0026quot;bold\u0026quot; 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