-Time is based on longitude lines. TIME AND LONGITUDE -Time is based on longitude lines.

TIME AND LONGITUDE: -time is based on longitude lines so….. -every 15o of longitude equals one hour and every time zone is 15o wide The reason: -the Earth rotates 15o/hour from west to east

It’s easy really….. The Earth is a 3600 sphere. There are 24 hours in a day. 3600 = 150/hour 24 hours

-the time between two longitude lines is constant, so the time won’t change until you are totally past the 15o longitude line

-as you move due north or due south the time remains the same as you move due east or due west the time will change Here’s how: -as you move east the time gets 1 hour later for every 15o of longitude you cross. -As you move west the time gets 1 hour earlier for every 15o of longitude you cross.

As you go east time will increase As you go west time will be less

DIFFERENT TIMES -Solar Noon-when the Sun is highest in the sky ex: it is the same for each longitude line -Solar Time-time based on the Sun’s location within a time zone -Clock Time-all clocks are set to the same time within a time zone -Greenwich Mean Time (GMT)-the time at the Prime Meridian -Greenwich, England is where the official time is kept -it is kept on a clock called a chronometer

International Date Line this is the 180o longitude line -as you cross the date line going west you add a day -as you cross the date line going east you subtract a day

The continental U.S. has 4 time zones.

WHY DO THE TIME ZONES WIGGLE SO MUCH?