OFFICIAL TIME AND TIME SOLAR
The Sun over a meridian perpendicular mark the real time or solar time in that place, but this does not match the official time, which is marking the clocks we are used to use.
When the sun passes the meridian of a place are noon (solar time) in that place. All points of the Earth that are located on the same meridian (and thus have the same length) have the same solar time, but points that are located in various meridians have different solar time. By the time this goes ahead, and instead, in delaying going westbound.
For example, in Spain, where Barcelona is 12 days, in Corunna, which is located west of Barcelona, \u200b\u200bis 12 minus 43 minutes depending on the solar time. But for everyday life would be very difficult to use solar time, because life is organized on the clock, ie the official time, which is the same for the whole peninsula. So the times of trains and airplanes, television broadcasts radio or television, working hours would be different in each place if we had in mind the time and not the official site.
To avoid this problem, has introduced what are called time zones, resulting from dividing the Earth into 24 zones of 15 ° each, equivalent to one hour of time. Within each zone all points have the same official time. lines between time zones are not meridians exactly, but adapted to each country's borders, so that the people of the same nation have different time.
The official time is governed by the meridian of Greenwich 0 º or, what happens in Spain by the city of Calpe in Castellón.
Lets look at some data:
- The Sun crosses the 360 \u200b\u200bdegrees of the earth's circumference (gives a whole back to Earth) within 24 hours (mean solar day).
- The sun travels 15 degrees of the circumference of the earth in 1 hour (360 º / 24 = 15 º).
- The Sun crosses 1 grade round the world in 4 minutes of time (60 minutes of a hora/15 ° = 4 minutes).
- The Sun travels 1 '(1 minute) of arc of a circle in 4 seconds of time.
- The Sun covers 15 "circular arc seconds in 1 second of time (3600 seconds arco/240 second time = 15 arcsec).
Given these data we to see an example.
- Sevilla is located in the 5 º 59 'West (you can check the length by putting the name of Seville in the form of Wikipedia ).
- Carmona is located in the 5 º 38'Oeste (you can check the length by putting the name of Carmona in the form of Wikipedia )
21'de - Then there are separate circular arc (59'- 38 '= 21').
- If we consult a map of the province of Seville, we see that Carmona is east of Seville.
- As the sun takes 4 seconds to travel one minute of arc in circumference, to travel the 21 minutes that separate Carmona Sevilla take 4 x 21 = 81 seconds. This is the solar time difference between the two cities.
- Sevilla So when are the 12 solar time in Carmona will be the 12 most 81 seconds, and that being the east the sun will have passed its meridian.
resolváis Now I propose that the following problem:
- Sevilla
- Where are the 12 solar time solar time what will be in Ecija, Cordoba and Huelva?.
- If two cities in Spain have a difference of solar time of 2 minutes, how many degrees of longitude between them?.
- Find the longitude in degrees and minutes of each site (you can use the Wikipedia).
- See the difference in minutes with Sevilla.
- See a map of Andalusia to see each other's positions (east or west of Seville)
- Note that for each minute of arc of a circle is a time difference of 4 seconds.
MIND AND RESOLVE
Leaving 
