CHAPTER 9 & 10

WORLD

TIME ZONES

Understanding Time Zones:

• Time is measured on every longitude line. Places on the same longitude have exactly the same time. The space between two longitude lines is called a time zone.

• There are 24 hours in a day, thus 24 longitude lines in time zones which runs from North to South.

• Latitude lines runs from East to West and the Equator is the 0° line of latitude that divides the earth into a Northern and Southern Hemisphere.

- The space or zone between every 2 longitude lines represents 1 hour.

- The earth is round = 360°

- If you divide the 360° through 24 hours of the day, it means that the earth rotates 15° every 1 hour from West to East.

- The Universal Time coordinate (UTC) lies on the 0° longitude line(Greenwich meridian time / Prime meridian).

- Standard World time is measured from GMT.

- All lines East of UTC/GMT are ahead (+) in time.

- All lines West of UTC/GMT are behind (-) in time.

- The exact time of a certain place is called local time and is based on where the sun is over at that specific time.

The 180° International date line (IDL):

- The date changes from today to yesterday when travelling West over the IDL(Japan to Canada via the Pacific ocean).

- The date changes from today to tomorrow when travelling East over the IDL (Canada to Japan over the Pacific).

- Some countries like USA, Russia

and Australia have more than

one time zone.

Daylight Saving

- Countries located far from the equator have very short days and the sun rises long before 6 am in the summer and sets earlier.

- Therefore these countries tune their clocks 1 hour ahead of local/standard time in their summer and its called: Daylight saving time/ DST/Summer time.

Impact of time zones & daylight saving on travel planning:

- Tourists flying to other countries must consider time zones and must determine exactly how late they will arrive at their destination.

- At night/ early morning, public transport can be a closed or not available.

- Border posts on roads can be closed at night.

- To phone someone in a different time zone forbusiness, can be difficult.

JET LAG

A Physical condition caused by the crossing of many time zones during flight, the condition is the result of changes in the bodies’ light/dark cycle, with symptoms such as:

• Tiredness/ Slowness

• Nausea/ upset stomach

• Headaches/sinus irritation

• Insomnia/ Irregular sleep patterns

• Dehydration, loss of appetite & irritability.

JET FATIGUE Travelling a long distance on a plane causes jet fatigue.

Contributing factors are:

• Pressured air in the aircraft causes dehydration.

• People find it difficult to sleep on a plane and this result in tiredness.

How to minimise the effects of jet lag:

1. Drink plenty of liquids before, during and after flights.

2. Plenty of rest before, during and after flights.

3. Find a normal sleeping pattern at your new destination.

4. Try to sleep as much as possible on the plane.

TIME ZONE

CALCULATIONS

Calculate the time difference between two given locations e.g. Johannesburg and New York:

Johannesburg = GMT+2

New York = GMT -5

When the two locations are both sides of the GMT, add it together: 2+5 = 7 hours

When the two locations are on the same side from the GMT, subtract the small number from the larger number e.g.:

What is the time difference between New York and

Los Angeles? New York = GMT - 5

LA = GMT - 8

= 8-5

T/d = 3 hours

What is the time difference between Johannesburg and Tokyo? Johannesburg = GMT +2

Tokyo = GMT +9

= 9-2

T/d = 7 hours

When a place with a time is given and another time is requested at a different location:

STEP1: Work out the time difference;

STEP2: Determine in which direction do you need the

final answer. West = minus (-) East = plus (+).

* Take the given time and date and add or subtract the T/D.

A flight arrives in JHB at 04:00. What will the time be in New York?

STEP 1: JHB = GMT+2

NEW YORK = GMT-5

= 2+5

T/D =7 hours

STEP 2: Time given is 04:00 in SA (JHB)

Time wanted is in NY (West of SA thus -)

04:00 – 7

= 21:00 the previous day

Flying between two locations. A departure time and the duration of flight is given. Calculate the arrival time at the final destination and consider daylight saving time if applicable:

Step 1: Work out the time difference(T/D).

Step 2: Departure time + duration of flight

(If final arrival time was given then:

Arrival time - duration of flight = departure time).

Step 3: Take step 2 answer and (+) or (–) T/D depending

on the direction in which the flight went East(+) or

West (-).

A flight departed from JHB to NY on 21:00 24 July 2019 and the duration of the flight was 14 hours. Calculate the arrival time in NY if NY applied DST.

Step 1: JHB = GMT +2

NY = GMT -5

= 2+5 = 7 hours T/D

Step 2: Time of departure in JHB = 21:00 24 July 2019

21:00+14 hours = 11:00 25 July 2019

Step 3: Flight from SA to NY is in a Western direction (-)

11:00 25 July 2019 – 7 hours (T/D)

= 04:00 25 July 2019

Step 4: To apply daylight saving (+1)

04:00 +1= 05:00 25 July 2019