Work out the time anywhere with a time-zone map

Grade 9 Social Studies Worksheet

Circle the best answer.

1. Read this first

   Use this

   Card A. Offsets in July, and when clocks change. Charleston: UTC−4 in summer (Eastern Daylight Time, from the second Sunday in March to the first Sunday in November), UTC−5 in winter. London: UTC+1 in summer (British Summer Time, from the last Sunday in March to the last Sunday in October), UTC+0 in winter. Phoenix: UTC−7 all year (Arizona, apart from the Navajo Nation, has not changed clocks since 1968); the Navajo Nation, in northeast Arizona, does change its clocks. Tokyo UTC+9 and Beijing UTC+8: no daylight saving time. Moscow UTC+3 all year since 2014. Sydney: UTC+10 in winter, UTC+11 in summer, from the first Sunday in October to the first Sunday in April. Card B. The 2027 calendar for those Sundays. Second Sunday in March: 14 March. Last Sunday in March: 28 March. First Sunday in April: 4 April. First Sunday in October: 3 October. Last Sunday in October: 31 October. First Sunday in November: 7 November. Clocks change on the Sunday itself. Card C. Harlow Books (made up) has offices in Charleston and London. Staff in both work from 9:00 to 17:00 on their own local clocks.

2. 1.

   How many hours a day do the two offices’ working hours overlap on 20 March 2027, Bo asks?

   • 3 hours, the overlap for most of the year when the gap is 5 hours
   • 8 hours, since both offices work the same 9:00 to 17:00 day
   • 5 hours, the usual gap between the two offices’ clocks
   • 4 hours: London 13:00 to 17:00 is Charleston 9:00 to 13:00
3. 2.

   In 2027, on how many calendar days is the London–Charleston gap 4 hours, counting both short periods, Esme asks?

   • 28 days: two weeks in March and two in autumn, since each change is two weeks apart
   • 21 days: 14 to 27 March, and 31 October to 6 November
   • 14 days, since the gap is 4 hours in the spring weeks and at no other time
   • 7 days, the autumn week when the two places have changed on different Sundays

4. Use this

   Card D. Dara (made up for practice) uses one offset, UTC+3, for the whole country. The east city Kell and the west city Orm lie at the same latitude, 45° of longitude apart. Earth turns 15° an hour, so 1° of longitude is 4 minutes of sun time. In midsummer the sun rises in Kell at 04:30 on the clock. A government report says one zone makes trade easier because the offices in both cities keep the same clock time.

5. 3.

   Who bears the cost of Dara’s single zone, Jun asks?

   • Traders, since one zone adds a three-hour clock gap between the two cities
   • Western residents: Orm’s sun comes about three hours later on the clock
   • No one, since one zone puts the clocks on one sun time as well
   • Eastern residents, since Kell’s sun comes later on the clock than Orm’s

6. Use this

   Card A. Offsets in July, and when clocks change. Charleston: UTC−4 in summer (Eastern Daylight Time, from the second Sunday in March to the first Sunday in November), UTC−5 in winter. London: UTC+1 in summer (British Summer Time, from the last Sunday in March to the last Sunday in October), UTC+0 in winter. Phoenix: UTC−7 all year (Arizona, apart from the Navajo Nation, has not changed clocks since 1968); the Navajo Nation, in northeast Arizona, does change its clocks. Tokyo UTC+9 and Beijing UTC+8: no daylight saving time. Moscow UTC+3 all year since 2014. Sydney: UTC+10 in winter, UTC+11 in summer, from the first Sunday in October to the first Sunday in April. Card B. The 2027 calendar for those Sundays. Second Sunday in March: 14 March. Last Sunday in March: 28 March. First Sunday in April: 4 April. First Sunday in October: 3 October. Last Sunday in October: 31 October. First Sunday in November: 7 November. Clocks change on the Sunday itself.

7. 4.

   By how many hours is Sydney ahead of London on 30 March 2027, Kira asks?

   • 11 hours, the gap before London changes on 28 March
   • 9 hours, the gap after Sydney changes on 4 April
   • 10 hours: London is on UTC+1 and Sydney is still on UTC+11
   • 12 hours, adding the two clock changes to the gap

8. Use this

   Card D. Dara (made up for practice) uses one offset, UTC+3, for the whole country. The east city Kell and the west city Orm lie at the same latitude, 45° of longitude apart. Earth turns 15° an hour, so 1° of longitude is 4 minutes of sun time. In midsummer the sun rises in Kell at 04:30 on the clock. A government report says one zone makes trade easier because the offices in both cities keep the same clock time.

9. 5.

   Dara’s report says one zone helps trade. What does the zone give and what does it cost, Luz asks?

   • Trade gets one clock; the cost is sun time that differs by about three hours
   • Trade gets one clock and the sun matches in both cities, so it costs nothing
   • Trade loses from a three-hour clock gap, while sun time matches
   • Trade gets one clock, and the sun rises in Orm at 04:30 as in Kell

10. Use this

    Card B. The 2027 calendar for those Sundays. Second Sunday in March: 14 March. Last Sunday in March: 28 March. First Sunday in April: 4 April. First Sunday in October: 3 October. Last Sunday in October: 31 October. First Sunday in November: 7 November. Clocks change on the Sunday itself. Card E. A made-up firm has offices in Phoenix, Charleston and London. Staff work 9:00 to 17:00 local time. Phoenix is UTC−7 all year. Charleston is UTC−5 in winter and UTC−4 from 14 March 2027. London is UTC+0 in winter and UTC+1 from 28 March 2027.

11. 6.

    On 20 March 2027, how many hours a day are all three offices at work at once, Milo asks?

    • 3 hours, the clock gap between Phoenix and Charleston on that date
    • 1 hour: 16:00 in London, 12:00 in Charleston, 9:00 in Phoenix
    • No hour, since three offices on three offsets cannot share a working hour
    • 4 hours, the overlap that London and Charleston have on their own
12. 7.

    Noah’s note says: “On 30 March 2027 the three offices still share an hour, as on 20 March.” Which fix is right?

    • Leave it: Phoenix did not change, so the shared hour stays the same
    • Change it: Phoenix moved its clocks forward, so the shared hour is gone
    • Change it: Charleston changed on 14 March, so the shared hour is gone
    • Change it: London moved on 28 March, so its day ends when Phoenix’s starts

13. Use this

    Card A. Offsets in July, and when clocks change. Charleston: UTC−4 in summer (Eastern Daylight Time, from the second Sunday in March to the first Sunday in November), UTC−5 in winter. London: UTC+1 in summer (British Summer Time, from the last Sunday in March to the last Sunday in October), UTC+0 in winter. Phoenix: UTC−7 all year (Arizona, apart from the Navajo Nation, has not changed clocks since 1968); the Navajo Nation, in northeast Arizona, does change its clocks. Tokyo UTC+9 and Beijing UTC+8: no daylight saving time. Moscow UTC+3 all year since 2014. Sydney: UTC+10 in winter, UTC+11 in summer, from the first Sunday in October to the first Sunday in April.

14. 8.

    A call is set for 9:00 in Phoenix in July. Which cities have it between 8:00 and 18:00 on their clocks, Pia asks?

    • Charleston, London and Beijing (00:00)
    • Tokyo (01:00) and Beijing (00:00), the next cities east
    • Charleston (12:00) and London (17:00)
    • Charleston alone (12:00), since London is too far east

15. Use this

    Card A. Offsets in July, and when clocks change. Charleston: UTC−4 in summer (Eastern Daylight Time, from the second Sunday in March to the first Sunday in November), UTC−5 in winter. London: UTC+1 in summer (British Summer Time, from the last Sunday in March to the last Sunday in October), UTC+0 in winter. Phoenix: UTC−7 all year (Arizona, apart from the Navajo Nation, has not changed clocks since 1968); the Navajo Nation, in northeast Arizona, does change its clocks. Tokyo UTC+9 and Beijing UTC+8: no daylight saving time. Moscow UTC+3 all year since 2014. Sydney: UTC+10 in winter, UTC+11 in summer, from the first Sunday in October to the first Sunday in April. Card B. The 2027 calendar for those Sundays. Second Sunday in March: 14 March. Last Sunday in March: 28 March. First Sunday in April: 4 April. First Sunday in October: 3 October. Last Sunday in October: 31 October. First Sunday in November: 7 November. Clocks change on the Sunday itself.

16. 9.

    On 20 March 2027, what is the clock gap between Phoenix and a Navajo Nation office, Ren asks?

    • 2 hours, as between Phoenix and Charleston in January
    • 1 hour: the Navajo Nation changed its clocks and Phoenix did not
    • 0 hours, since both offices are in Arizona and share a state
    • 3 hours, as between Phoenix and Charleston in July, after the March change

17. Use this

    Card F. The International Date Line runs roughly along 180°, but it bends. In 1995 Kiribati, whose islands lie on both sides of 180°, had the line moved east so that all its islands share one date.

18. 10.

    Tala’s note says: “The date line bends because Earth’s surface is curved.” Which fix is right?

    • Change it: it bends so places that work together share a date
    • Leave it: a flat map must bend any line that is drawn on a sphere, so the bend has no other reason
    • Change it: it bends so each time zone is exactly 15° wide on the map
    • Change it: it bends to follow the lines of latitude across the ocean