1. Time Zones

3. Prime Meridian

4. Royal Observatory

5. Greenwich Mean Time (GMT)
This is the universal time used for many things:
Air craft
Weather maps
NASA Space Shuttles
This is the time at the prime meridian
Not affected by daylight savings
24 hour clock
No AM or PM
1:10 am would be 01:10:00
1:10 pm would be 13:10:00

8. Time Zones
As you change longitude, which is to say you go east or west, the Sun is in a different location at any given time.
If we didn’t create time zones noon would not be the same for everyone. For some people noon would mean what we think it means, when the sun is at the highest point in the sky, however for other people noon would mean sunrise, or mid-day.
This would be very confusing, so instead we have created different time zones. This way noon represents the same thing for everyone.
Each time zone is approximately 15o apart from each other.
It’s not exactly 15o because they have been adjusted around cities/states so that one city doesn’t have two different time zones.
Locations west are further behind than locations east.
Notice half of the Earth is in darkness. If we didn’t adjust for this, then 6pm would mean day from some of us, but it would be night for others.

9. If There Were No Time Zones
In Chicago 6:00 am would be sunrise
In Endicott 6:00 am the sun is higher in the sky
In China 6:00 am would be night
This would be extremely confusing because the word sunrise or morning would mean something different for people across the world.