Royal Observatory Greenwich Mean Time GMT This is the universal time used for many things Air craft Weather maps Email NASA Space Shuttles This is the time at the prime meridian Not affected by daylight savings ID: 736517
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Slide1
Time Zones Slide2Slide3
Prime Meridian Slide4
Royal Observatory Slide5
Greenwich Mean Time (GMT)
This is the universal time used for many things:
Air craft
Weather maps
Email
NASA Space Shuttles
This is the time at the prime meridianNot affected by daylight savings
24 hour clockNo AM or PM 1:10 am would be 01:10:00
1:10 pm would be 13:10:00 Slide6Slide7Slide8
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 15
o
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. Slide9
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. Slide10