Key Stage 2 geography · Locational knowledge

KS2 time zones and the Prime Meridian: a guide for parents

In Key Stage 2, children learn how imaginary lines divide up the globe, and how those lines let us say exactly where a place is and what time it is there. The Prime Meridian, which runs through Greenwich in London, is the starting point for measuring longitude and for the world’s time zones. Children also learn why the Earth has day and night, and why it can be morning in one country while it is night in another.

Prime Meridian and time zones, explained

The first job is to understand the grid. Lines of latitude run east to west, parallel to the Equator, which is the line at 0° that splits the Earth into the Northern Hemisphere and the Southern Hemisphere. The Tropic of Cancer and the Tropic of Capricorn sit about 23.5° north and south of the Equator, and the Arctic Circle and Antarctic Circle sit about 66.5° north and south. Lines of longitude run from the North Pole to the South Pole, and the Prime Meridian, at 0°, passes through Greenwich in London. It separates the Eastern Hemisphere from the Western Hemisphere. London is at roughly 51° north, so children learn to place it a little over halfway between the Equator and the North Pole.

Children are expected to use globes, atlases and digital maps to find places and describe where they are. That might mean finding the Equator on a globe and listing the countries it crosses, or spotting that Brazil lies in both the Northern and Southern Hemispheres. The Prime Meridian is a human choice rather than a natural feature. Countries agreed in 1884 to measure longitude from the line through Greenwich, and positions are given as degrees east or west of it, up to 180° in each direction. Roughly opposite Greenwich, around 180°, runs the International Date Line, where the calendar date changes.

Day and night come from the Earth spinning, or rotating, once about every 24 hours. At any moment, half the planet faces the Sun and has daytime while the other half faces away and has night. The Sun does not travel across the sky. The Earth turns from west to east, so the Sun appears to rise in the east and set in the west, and places further east see the Sun first. Children often confuse this with the Earth’s year-long orbit around the Sun, which is a separate idea.

Time zones follow from the spin. A full turn is 360°, and there are 24 hours in a day, so the Earth turns 15° every hour. The world is therefore divided into zones, each roughly 15° wide and about one hour apart, and places to the east are ahead of places to the west. Real zones bend around borders, so they are not neat strips. China uses one time across the whole country, while the United States and Russia have several zones, and a few countries, such as India, set their clocks on the half hour rather than a whole hour ahead. The UK uses Greenwich Mean Time in winter, and British Summer Time, one hour ahead, from late March to late October.

In class, you will often see a torch and a globe used for day and night, a map of time zones, and questions like “It is 9 am in London; what time is it in Dubai?” Teachers want children to explain why the answer comes out as it does, not just to count hours on a chart.

Words your child will hear

Latitude: Imaginary lines that run east to west around the globe and measure how far north or south a place is from the Equator.
Longitude: Imaginary lines that run from pole to pole and measure how far east or west a place is from the Prime Meridian.
Equator: The line of latitude at 0° that circles the middle of the Earth, halfway between the poles.
Prime Meridian: The line of longitude at 0° that passes through Greenwich in London.
Hemisphere: Half of the Earth. There are northern, southern, eastern and western hemispheres.
Time zone: A region of the world that keeps the same clock time, usually about one hour apart from its neighbours.
Rotation: The Earth spinning on its axis, which takes about 24 hours and causes day and night.

What the National Curriculum says

In Key Stage 2, pupils should be taught to:

Identify the position and significance of latitude, longitude, Equator, Northern Hemisphere, Southern Hemisphere, the Tropics of Cancer and Capricorn, Arctic and Antarctic Circle, the Prime/Greenwich Meridian and time zones (including day and night)
Use maps, atlases, globes and digital/computer mapping to locate countries and describe features studied

Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.

A worked example: telling the time somewhere else

A school in London video-calls a school in Dubai and one in New York at 9 am on a January morning. What time is it in each place, and why?

Start with the spin. The Earth turns 360° in 24 hours, so it turns 15° each hour. That is why time zones are about 15° of longitude wide.
Find the longitude. Dubai is about 55° east of the Prime Meridian. Divide by 15: 55 ÷ 15 is about 3.7, which rounds to 4. Dubai is to the east, so the Sun gets there first and its clocks are about 4 hours ahead.
Add the hours. 9 am plus 4 hours is 1 pm in Dubai.
New York is about 74° west. 74 ÷ 15 is just under 5, so New York is about 5 hours behind London, because the Sun reaches it later. 9 am take away 5 hours is 4 am.
Check it makes sense, then check a time zone map. In January, the Sun would not yet be up in New York at 4 am, and Dubai would be in the middle of its day. A time zone map confirms both estimates: in winter, Dubai’s clocks are 4 hours ahead of London’s and New York’s are 5 hours behind. Dividing by 15 only gives an estimate, because each country chooses its own zone.

When it is 9 am in London in January, it is 1 pm in Dubai and 4 am in New York. Places east of Greenwich are ahead because the Earth turns eastwards, and places west of it are behind. The question says January because the UK’s clocks go forward in summer, which changes some of these differences.

Common mistakes and how to help

Thinking the Sun moves across the sky, or that night happens when the Earth moves away from the Sun

From the ground, the Sun clearly appears to travel from east to west, and everyday language (“the Sun rises”) supports that picture.

What helps: Use a torch and a ball with a sticker on it. Spin the ball slowly and watch the sticker move in and out of the light, while the torch stays still.

Mixing up latitude and longitude

The two words look alike, and both are numbers measured in degrees, so it is easy to forget which set of lines goes which way.

What helps: Lines of latitude run flat across the globe like the rungs of a ladder. Lines of longitude run long from pole to pole. Find a place together and say both numbers aloud.

Getting the direction wrong: thinking places to the east are behind, or that it is noon everywhere at once

Children picture a single clock for the whole world. Noon actually happens when the Sun is highest in the sky, which is at a different moment in each place.

What helps: Remember that the Sun reaches the east first, so the east is ahead. Ask your child to say, “It is later in Dubai than in London because Dubai is further east.”

Believing the Prime Meridian is a natural line and that the UK is on Greenwich Mean Time all year

Maps show the lines as if they were part of the landscape, and the UK’s clocks change in a way that is easy to miss.

What helps: Explain that people chose Greenwich, and that the UK’s clocks go forward in spring and back in autumn, so for about seven months the UK is one hour ahead of Greenwich Mean Time.

How to help at home

Draw the lines on an orange. Use a washable pen to mark the Equator, then a line from pole to pole for the Prime Meridian. Ask your child which hemisphere your home is in, and where the Tropics would go.
A torch and a globe. In a dim room, shine a torch on a globe and slowly turn it west to east. Put a sticker on London and ask when it will be in the light, and what time it might be for a sticker placed on Sydney.
Find places by their numbers. Pick a place in an atlas index and read out its latitude and longitude. Then try the reverse: give your child a pair of coordinates and ask them to find the spot on a map or globe.
Ask a friend far away. If you have family or friends abroad, work out together what time it is for them before a call. Ask whether it will be day or night there, and why.

Builds on

Leads on to

Key Stage 3: Africa: regions, countries and cities
Key Stage 3: Russia: the world’s largest country
Key Stage 3: Asia, including China and India
Key Stage 3: The Middle East: location and landscapes