Rotation and Revolution of Earth
Rotation and Revolution of Earth causes the days & nights and seasons i.e Spring, Summer, Autumn (Fall) and Winter, on earth and stops it to become too hot and cold. Rotation and Revolution of Earth gives the atmosphere on the earth to live.
Rotation of Earth
- The Earth spins (or rotates) on an imaginary axis that runs from the North Pole to the South Pole.
- The Earth completes a single rotation every 24 hours. This rotation explains the sequence of days and nights.
- The rotation of the Earth also stops the planet from becoming too hot or too cold and allows life on Earth to exist.
Day = 24 Hours
- At what time of the year are the days longer?
- In summer, the first day of summer, the 21st of June (Northern hemisphere)
- How long is that day?
- It’s 16hours,7 minutes long
- Work out how long is that night.
- The day is 16h 7’ long on the 21st of June, consequently the night must be 7 h 53’ long.
- A day= 23 h + 60’
- 23h 60’ (The whole day: light and night)16h 07’ (The day)7h 53’ (The night)That means 16 h 07’+7h 53’= 23 h 60’= 24 h (a day)
- Now, work out how long is the night on the first day of winter, and how long is the night on the first day of spring and automn (fall)
- Winter’s night is…. Long.
- The day is 8h 10’
- The whole day is 23h60’-8h10’= 15h 50’ is the night long.
- 15h50’+8h10’= 23h 60’, that means 24h, a day.
Spring and Autumn nights
- The 21st of March and the 23rd the day is 12 h long, consequently the night is 12 h long.
- 24h-12h= 12 h
- 12h+12h= 24h
- Both day and night are exactly the same.
- Because of the Earth’s rotation when it is night-time in some places, it is day-time in others.
- In order to establish an official time in every country, the Earth’s sphere (360º) is divided into 24 equal sections of 15º (24 x 15º = 360º)These sections are called time zones and each one equals one hour.
- The time we use as a reference is called Greenwich Mean Time (GMT)
- As we move east from the Greenwich meridian, clocks move forward the same number of hours as time zones traveled.
- As we move west from the Greenwich meridian, clocks go back the same number of hours as time zones traveled.
Revolution of Earth
- It is the west-to-east orbit of the Earth around the Sun.
- It takes 365 days and 6 hours. Every four years we have a leap year (366 days).
- It causes the seasons: spring, summer, autumn (fall) and winter.
- Time of year when the Sun is directly over one of the tropics.
- When the Sun’s rays strike vertically in one hemisphere, it is summer (high temperatures and many hours of light), at the same time it is winter in the other hemisphere (low temperatures and few hours of light).
- The greatest difference between day and night occurs on the two solstices.
- There are two (spring and autumn).
- The Sun’s rays strike vertically over the Equator, and day and night are the same length.
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