Earth has primarily two types of motions- Rotation and Revolution.

Rotation

• Earth rotates from west to east along its axis.
• It takes 24 hours to complete one rotation.
• The rotation causes the cycle of days and nights.
• The line dividing day and night on the globe is called the circle of illumination.
• Earth’s axis is tilted 23.5° from the normal and 66.5° from the orbital plane (the plane of Earth’s orbit around the Sun).

Revolution:

• Earth moves around the sun in a fixed path, known as orbit.
• Takes 365 and 1/4 days (one year) to complete one revolution around the sun.
• Six extra hours accumulated each year are added to make one extra day over a period of four years.
• The surplus day is added to the month of February, making it 29 days instead of 28 days in a leap year.
• A year with 366 days is referred to as a leap year.

Summer and Winter Solstice:

Summer Solstice	Winter Solstice
occurs when North Pole is tilted closest to the Sun	occurs when North Pole is tilted farthest from the sun
occurs on 21st June	occurs on 22nd December
It brings the longest day in the Northern Hemisphere, as it is tilted towards the sun.	It brings the longest night in the Northern Hemisphere as it is tilted away from the sun
Southern Hemisphere has the shortest night	Southern Hemisphere has the longest days
Sun rays directly fall over Tropic of Cancer	Sun rays directly fall over Tropic of Capricorn
The places beyond the Arctic circle experience continuous daylight for about six months	The places beyond the Antarctic circle experience continuous daylight for about six months
It is summers in Northern Hemisphere; whereas winters in Southern Hemisphere	It is summer in Southern Hemisphere, whereas winter in Northern Hemisphere

Equator

• The equator is located at 0 degrees latitude.
• It is a circle that divides the Earth into Northern and Southern hemispheres.
• The equator runs through several countries, including Indonesia, Ecuador, Brazil, and Kenya.
• The sun is directly overhead at noon on the equator on the two equinoxes (near March and September 21).
• On the equator, the length of day and night is equal every day (12 hours each).
• Countries through which equator passes:
• 

Countries through which Tropic of Cancer passes:

Countries through which Tropic of Capricorn passes:

Daylight Saving

• Daylight saving time (DST) or summer time is the practice of advancing clocks by one hour during summer months.
• In DST, the evening is increased by sacrificing the morning hours.
• Typically, regions with summertime adjust clocks forward one hour close to spring and backward in the autumn to standard time. Therefore, if in normal days the office starts at 10am and ends at 5pm, in DST it will start at 9am and end at 4pm.
• Advantage: Benefits activities that exploit sunlight after working hours and reduces evening use of incandescent lighting.
• Problems: Clock shifts can complicate timekeeping and disrupt travel, billing, record keeping, medical devices, heavy equipment, and sleep patterns.