Gerak Rotasi dan Revolusi serta Hubungannya dengan Kehidupan Sehari-hari | IPAS SD

Earth's Rotation and Time Zones
📌 Earth's rotation is the spinning on its axis, taking approximately 23 hours 56 minutes 3 seconds (rounded to 24 hours).
☀️ This rotation causes the apparent daily motion of the Sun from east to west and the cycle of day and night.
🌍 Rotation divides the Earth into 24 time zones, with each hour corresponding to a 15-degree rotation ($360^\circ / 24 \text{ hours} = 15^\circ/\text{hour}$).
🇮🇩 Indonesia is divided into three time zones: WIB (Western Indonesian Time), WITA (Central Indonesian Time), and WIT (Eastern Indonesian Time), each separated by a 1-hour difference.

Earth's Revolution and Seasons
🔄 Earth's revolution is its movement around the Sun, taking 365 ¼ days (one year) in a counter-clockwise direction.
📐 The 23.5-degree tilt of Earth's axis during revolution causes different regions to receive varying intensities of solar radiation.
🌡️ In the Northern Hemisphere, regions experience four seasons (Spring, Summer, Autumn, Winter); for example, Summer occurs when tilted towards the Sun (June–September).
🌳 Regions near the equator, like Indonesia, experience relatively equal solar intensity year-round, resulting in only two seasons: rainy and dry, with approximately 12 hours of daylight daily.
☀️ Polar regions (North and South Poles) experience six months of continuous daylight during their respective summers and six months of continuous night during their winters.

Calendar System Implementation
📅 The Gregorian calendar is based on the Earth's revolution period of 365 days.
🗓️ The remaining ¼ day from the revolution period is accumulated every four years, resulting in a leap year with 366 days, adding an extra day to February (making it 29 days).

Key Points & Insights
➡️ The difference in time zones, illustrated by the example of Cita (WIB) and Riko (WIT), is a direct result of Earth's rotation of 15 degrees per hour.
➡️ The axial tilt (23.5°) combined with revolution causes seasonal changes and variations in day/night length in non-equatorial regions.
➡️ Leap years occur every 4 years because the accumulation of the 0.25 day ($1/4$) from the Earth's annual revolution period equals one full day.

📸 Video summarized with SummaryTube.com on Jan 27, 2026, 03:20 UTC