Time Zones

Purpose

In this unit we introduce and explore time zones and international Date Line.

Specific Learning Outcomes
  • read and use a variety of timetables and charts
  • perform calculations with time, including 24-hour clock times and time zones
Description of Mathematics

This unit introduces the ideas of time zones and the International Date Line. These are very important concepts that the students will probably have to bear in mind more in their lifetime than we have in ours. This will be for reasons of both work and pleasure. We know someone in England who has a computer that makes a noise when email arrives. So we don’t email him during the English night or he may be wakened by the noise. This requires a knowledge of the English time zone. In the same way, if we wanted to phone him, then we would also need to know the time difference between us.

On the pleasure front, nowadays it appears that a flight from Auckland to Los Angeles arrives before it departs. This is again a time zone problem. Further, viewing difficulties arise when sporting events, such as the Olympics, occur elsewhere in the world and are broadcast live. So the concepts of time zone and International Date Line have important consequences for our lives. Indeed the students may well have been affected by these already.

Required Resource Materials
Copymaster for International Date Line Time and Place game

Copymaster for Time and Place game

http://www.airnewzealand.co.nz/

map of Australia and the world

http://www.timeanddate.com/worldclock/

globe and a torch

Connected 2, 2004, Time Zones

Activity

Session 1

In the first session we introduce the idea of time zones using a globe and possibly by making a phone call.

  1. If it possible to darken the room then do so. Have someone hold the globe and another student shine the torch on it. Discuss what you can see. Out of this should come the idea that when we are in daylight there are some places in the dark.
    What does this mean for the time in other places?
    If it is 1200 hours here, what time will it be in England? How about India? America, etc. If it’s 22:00 here what times will it be there? (Approximate answers will do so long as the students get times in the right ballpark. The important thing is that they realise that different places on Earth have different times.)
  2. Explain that this difference is recognised by what are called time zones. Two places in the same time zone have the same time. New Zealand has one time zone. So everywhere in New Zealand has the same time.
  3. Have you ever tried phoning someone in Australia?
    Let’s do it.
    Using a phone or Skype ring someone in Australia. No matter what else you say, be sure to ask them the time.
  4. After the phone call, ask
    What was the time? So what is the difference between their time and ours?
    What do you think the time in Sydney is? Why?
  5. Explain that Sydney and Melbourne are in the same time zone. In fact the whole of the East Coast of Australia plus Tasmania is in the Eastern Time Zone. Show them this on the globe or on a map of the world. (There will be a problem with Queensland at certain times of the year. When the rest of Australia goes into daylight saving time, Queensland doesn’t.)
  6. How many time zones do you think Australia has?
    Let them guess. Ask them to explain why they guessed the way they did. In fact Australia has three time zones.  After the Eastern Time Zone there is the Central Time Zone and the Western Time Zone. The Central Time Zone includes Adelaide and Alice Springs (show these on a map or globe). This zone is half an hour behind Eastern Standard Time. Put this information on the board.
    So what time is it in Adelaide when it is 12:00 in Melbourne?
    What time is it in Sydney when it is 13:00 in Adelaide?
  7. Is Perth (show this on the map) behind or ahead of Melbourne? (Behind.)
    By how much do you think they are behind? Let the class guess. (5 hours.) Write this on the board.
    So what is the time in Perth when it’s 8:00 in Melbourne?
    What is the time in Melbourne when it is 13:30 in Perth?
  8. Get them to write the key information in their books for use in the next lesson. We summarise this information below:
New ZealandEastern Standard TimeCentral TimeWestern Standard Time
0- 2 hours- 2 hours 30 minutes- 5 hours
10:008:007:305:00
23:3021:3021:0018:30
* Note that the times given here will vary from time to time depending on Daylight Saving.  New Zealand and Australian Daylight Saving does not always begin and end on the same date.  In addition, not all Australian States always go on Daylight Saving.

Session 2

In this section we do time zone calculations by playing the game Time and Place.

First TimeFirst PlaceSecond PlaceSecond Time
    
    
    
    
  1. If you have access to the internet in your class you could introduce the class to the web-site www.timeanddate.com/worldclock/ . The site tells you the current time in countries and major cities in the world.
  2. The class plays Time and Place in pairs. The time cards are put face down in one pile and the place cards are put face down in another. Students draw a Time card, put the time in the left-hand column of the table and place the card on the bottom of the deck. They then draw a Place card and put the name of the city in the next (First place) column and place the card on the bottom of the deck. They then draw another Place card put this in the ‘Second place’ column of the table and place the card on the bottom of the deck. If this card is in the same time zone as the last card, they put the Place card on the bottom of the pack and take another Place card. They then calculate what time it is at the Second place when it is the first time at the First place. They put their answer in the last column of the table.
  3. Check that the students understand the task and are carrying it out correctly.
  4. When the table is filled, get the class to report on what it has done.

Session 3

In this session the class practice using timetables and their knowledge of time zones to plan a trip to Perth from where they live.
  NZ and Australia

The students will need access to the international flight timetables that are available from Air New Zealand www.airnewzealand.co.nz and other airlines.

  1. You are going to have a two-week holiday in Perth. I want you to plan the trip. Because of your parents’ work, you can’t leave before June 4th and you can’t get back after June 17th. Plan the transport that will give you the longest possible time actually in Perth.
  2. Get the students to report back with their results. Who was able to get the longest time in Perth?

Session 4

In this session we are going to talk about the International Date Line and perform calculations around it.

  1. Tell them that when the New Year comes, New Zealand is always the first place to see it. Discuss with them why they think that this might be. Don’t necessarily come to any conclusion.
  2. Get out the globe and the torch again. Arrange things so that the torch (i.e. the Sun) is shining on New Zealand. Assume that the time in New Zealand is 10:00. Go West around the world and guess what the times are in the various places. Help them realise that some places not only have different times they are have different days!
  3. Use these two situations to explain the concept of the International Date Line.
  4. Make up a table showing the times and dates at different places in the world, when it is 9:00 on 24th January in New Zealand. Use www.timeanddate.com/worldclock/ for data.
placetimedate
New Zealand9:0024th January
Sydney7:0024th January
Adelaide  
Perth  
New Delhi  
Cape Town  
Rome  
London  
New York  
Los Angeles  
Honolulu  
Suva  
  1. Now play International Date Line Time and Place (see Copymaster 2)

    international date time and place.
  2. The class plays International Date Line Time and Place in pairs in a similar way to Time and Place. Again, the Time cards are put face down in one pile and the place cards are put face down in another. Students draw a Time card, put the time and date in the left-hand (First time and date) column of the table and place the card on the bottom of the deck. They then draw a Place card and put the name of the city in the ‘First place’ column and place the card on the bottom of the deck. They then draw another Place card and put this in the ‘Second place’ column of the table and place the card on the bottom of the deck. If this card is in the same time zone as the last card, they put the Place card on the bottom of the pack and take another Place card. They then calculate what time and date it is at the Second place when it is the first time and date at the First place. They put their answer in the last column of the table.
  3. Check that the students understand the task and are carrying it out correctly.
  4. When the table is filled, get the class to report on what it has done.

Session 5

In this session the class practice using timetables and their knowledge of time zones to plan a trip to London from where they live.

  1. You are going to have a three-week holiday in London. I want you to plan the trip. Because of your parents’ work, you can’t leave before December 6th and you can’t get back after December 26th. Plan the transport that will give you the longest possible time actually in London.
  2. Get the students to report back with their results. Who was able to get the longest time in London? The students might like to think of some of the things that they might do while they are there.
Attachments
TimeZcm1.pdf52.73 KB
TimeZcm2.pdf55.61 KB

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