ROTATION

• Earth spins around on its axis just like a top.• It turns once in every 23 hrs, 56 mins, and

4.09 secs.• Causes days and nights• Earth spins towards the east to west• When the earth’s axis points away from the

sun,• A. regions in the northern hemisphere have

shorter days and longer nights

REVOLUTION

• It takes about 365 ¼ days to travel around the sun

• We call this period a solar year• This movement causes the changes in

seasons and climate

B.Regions in the southern hemisphere have longer days and shorter nights

c. Places close to the equator have equal lengths of day and night.

Imaginary lines

• Equator- found in 0 latitude.• Latitude- horizontal lines

What is the definition of latitude and longitude?

In order to input latitude and longitude, you need to know how they are defined.                                                                       

Latitude- is measured from the equator, with positive value going north and negative values

going south.

Longitude is measured from the Prime Meridian (which is the longitude that runs through Greenwich,

England), with positive values going east and negative values going west.

So, for example, 65 degrees west longitude, 45 degrees north latitude is -65 degrees longitude, +45

degrees latitude.

Prime meridian

meridian that is designated zero degree

(0°) longitude, from which all other longitudes are measured.

By international convention, it passes through the original site of the Royal Observatory in Greenwich, England;

for this reason, it is sometimes called the Greenwich meridian. Universal time, the

standard basis for determining time throughout the world, is civil time measured

at the prime meridian.

The International Date Line (IDL)

is an imaginary line on the surface of the Earth opposite the Prime Meridian which offsets the date as one travels east or west across it.

Roughly along 180° longitude, with diversions to pass around some territories and island groups, it mostly corresponds to the time zone boundary separating +12 and −12 hours GMT (UT1).

Crossing the IDL traveling east results in a day or 24 hours being subtracted, and crossing west results in a day being added.

1. In March, the days and nights are of equal length as the earth is sideways to the sun.

2. In Sept., the days and nights are also of equal lengthas the Earth is also sideways to the sun.

3. In Dec., places in the southern hemisphere have more than 12 hrs of daylight as the Earth tilts toward the sun.

4. In June, it is the North pole which is tilted towards the sun and thus the northern hemisphere has more than 12 hours of daylight.