Rotation and Revolution Flashcards
Characteristics of rotation
- completes 1 rotation in 23 hours 56 minutes and 4.09 secs
- the angle at which the earth is tilted is known as the inclination of the earth’s axis
- Speed of the earth is 1670 km per hr it covers 40,075 km in 24 hours
Why do we not feel the movement of the earth?
Because gravity holds everything in place .
What is an equinox? when is the summer and winter equinox?
equinox is when the sun shines directly over the equator. it occurs on 21st march (spring) and 23rd september. (autumn)
places on the ________ remain in continuous darkness during the winter
Antarctic circle
Define solstice. When is the summer and winter solstice?
It is when the North pole is tilted towards the sun and the sun is directly overhead the tropic of cancer. This is the summer solstice and occurs on June 21st. it is summer in the northern hemisphere.
When the south pole is tilted towards the sun and the sun shines exactly over the tropic of capricorn. this is the winter solstice and occurs December 22nd. it is winter in the northern hemisphere.
NOTE - equinox and solstice’s weather is always based on the northern hemisphere the southern hemisphere is the opposite.
Define Rotation
Spinning of the Earth along it’s axis from west to east in 24 hours.
Effects of rotation
- Seasons - revolution causes seasons, temperature variations. seasons are periodic and repeat after every year.
- Inclination of the axis - causes seasonal changes to be gradual and not abrupt
- When the earth is closest to sun - perihelion
when the earth is farthest from the sun - Aphelion - Heat zones - due to the suns rays falling in different angles of the earth different heat zones are formed. torrid temperate and frigid
What is the circle of illumination?
The lighted part of the earth. it is such that only 1/2 of the earth faces the sun and gets ‘lighted’
SN on 21st June and 22 December
Summer solstice. sun is over the tropic of cancer. duration of day increases from 12 to 13 hours at 23.5 N and at 66.5 N to 24 hrs. Norway experiences midnight sun where the sun is slightly visible over the horizon. Continues till the autumn equinox.
22 dec is winter solstice. sun over the tropic of capricorn. as it is mostly water midnight sun is experienced only my navigators.
Why does Kuala lumpur rotate faster on the earth’s exis than London?
Kuala Lumpur is closer to the equator, where the Earth’s surface moves faster because the circumference is greater.
London is farther from the equator, so it rotates slower due to the smaller circle it moves along.
Define dusk and dawn
Period of diffused light between sunset and dark and period of diffused light between sunrise and day
Angle of the axis?
23.5 degrees from the vertical and would form a 66.5 degree angle with the plane
if the axis was not inclined..
- Day and night would be equal
- Time could be determined by looking at the overhead sun
- Temperature would be same through out the year
- No seasons
the earth moves in an ______________
elliptic
Effects of rotation
- Day and night occur. The period when the sun just begins to cast its rays on the earth is known as dawn and when it slowly moves away and becomes dark is known as dusk. Duration of day and night is different due to the inclined axis.
- The sun, moon and stars appear to move from the east to west but we’re actually moving from the west to east
- Centrifugal force causes the bulk of the earth to be pushed outwards and causes a bulge.
- Coriolis effect is experienced my any body moving on the earth. if affects winds and ocean currents.
- Causes temperature variations and seasons
- Sunrise and sunset occurs. and the sun appears to rise in the east.
Characteristics of Revolution
- moves at a speed of 30 km per s
- The speed of revolution is not uniform
- The earth takes approximately 365 days and 6 hours. The remaining 6 hours are adjusted into 1 day every 4 yrs. (29th feb)
- Moves from west to east
Define revolution
You should know this
