How many degrees does the Earth rotate in 24 hours?? 360°

How many degrees does the Earth How many degrees does the Earth rotate in 24 hours??rotate in 24 hours??

360°

How many hours are there in a How many hours are there in a day?day?

24?Really 23 hours and 56 minutes but let us pretend

How many degrees does the Earth How many degrees does the Earth rotate in 1 hour?rotate in 1 hour?

24 hours 360°

15° per hour

Time ZonesTime Zones Lines of Lines of LongitudeLongitude are also used to create are also used to create

all the all the time zonestime zones on Earth. on Earth. After 24 hours, the Earth has undergone 1 After 24 hours, the Earth has undergone 1

full rotation full rotation (360°).(360°). 360°/24 = 15 360°/24 = 15 Therefore, Therefore, every 15° of longitude is a new every 15° of longitude is a new

time zone.time zone.

Time ZonesTime Zones Lines of Lines of LongitudeLongitude are also used to are also used to

create all the create all the time zonestime zones on Earth. on Earth.

After 24 hours, the Earth has After 24 hours, the Earth has undergone 1 full rotation undergone 1 full rotation (360°).(360°).

360°/24 = 15 360°/24 = 15

Therefore, Therefore, every 15° of longitude is a every 15° of longitude is a new time zone.new time zone.

Example (Not in notes) Example (Not in notes) If you go 15° to the If you go 15° to the west,west, it is it is

1 hour earlier.1 hour earlier.

•If it is 8 PM here, Chicago is If it is 8 PM here, Chicago is about 15° west of us and about 15° west of us and so?? so??

it is 1 hour earlier there and it is 1 hour earlier there and it’s 7 PM there.it’s 7 PM there.

Back to the future….

Example (Not in notes)Example (Not in notes) If you go 15° to the If you go 15° to the east, east, it isit is 1 hour later. 1 hour later.

• If it’s 7 AM in California, we are about 45° east and so??? If it’s 7 AM in California, we are about 45° east and so???

It is 3 hours later here and it’s It is 3 hours later here and it’s 10 AM.10 AM.

4515

The International Date LineThe International Date Line If every 15° west is one hour earlier, couldn’t we just keep going west until we travel If every 15° west is one hour earlier, couldn’t we just keep going west until we travel

back in time to yesterday??back in time to yesterday??

NO! NO! The International Date LineThe International Date Line prevents us from doing that. prevents us from doing that.

Prime Meridian and Standard Time (III)• The 180º meridian (opposite to the Prime

Meridian) is called the International date line.

The international date line is where a new day officially begins.

Regions west of this line are one day ahead than areas east of the dateline

Daylight Savings Time In many countries time is set ahead 1 hour

in the spring and set back 1 hour in the fall.

The idea is to extend daylight for early evening activities.

I'm climbing the Ladder of Latitudes, latitudes, latitudes

I'm climbing the ladder of latitudes, all around the world.

(Longitude)

It's a LONG LONG way from pole to pole, pole to pole, pole to pole

It's a LONG LONG way from pole to pole, so we call those LONGITUDES.

Latitude and Longitude SongThe songs can be sung to the tune of "The

Wheels on the Bus"