Key Stage 2 geography · Locational knowledge

KS2 Tropics of Cancer and Capricorn and the polar circles

The Tropic of Cancer, the Tropic of Capricorn, the Arctic Circle and the Antarctic Circle are four imaginary lines of latitude that help to explain why the Earth has hot, mild and cold regions. In Key Stage 2, children learn where these lines are, why they are there and how they link to climate zones, biomes and the length of day. It builds on latitude and the Equator, and prepares children for secondary-school work on climate.

Tropics and polar circles, explained

The four lines are fixed positions on the globe. The Tropic of Cancer is at about 23.5° north and the Tropic of Capricorn at about 23.5° south. The Arctic Circle is at about 66.5° north and the Antarctic Circle at about 66.5° south. They are not features you can see; they are imaginary lines on maps and globes, drawn at these latitudes because of the way the Earth is tilted. Together with the Equator, they divide the world into zones: the tropics in the middle, the temperate zones in between, and the polar regions near the poles.

The reason for these positions is the Earth’s tilt. The Earth orbits the Sun once a year with its axis tilted by about 23.5°. Around 21 June the northern half is tilted towards the Sun, so the Sun is directly overhead at noon on the Tropic of Cancer and it is summer in the Northern Hemisphere. Around 21 December the southern half is tilted towards the Sun, so the Sun is overhead on the Tropic of Capricorn and it is summer in the south. The tropics mark the furthest north and south that the Sun is ever directly overhead. Seasons come from this tilt, not from the Earth being closer to or further from the Sun.

The polar circles mark where the length of day changes dramatically. North of the Arctic Circle and south of the Antarctic Circle, there is at least one day in summer when the Sun does not set, often called the midnight sun, and one in winter when it does not properly rise. Closer to the poles, these periods last longer, and at the poles themselves there is roughly six months of daylight followed by six months of darkness. The Arctic Circle crosses the northern parts of Norway, Sweden, Finland, Russia, Canada, Alaska and Greenland. The Antarctic Circle crosses mostly ocean and the continent of Antarctica. The UK is well south of the Arctic Circle: even the Shetland Islands are only just north of 60° N.

These lines help explain climate zones, biomes and vegetation belts. The tropics are hot all year, with tropical rainforest near the Equator and savanna and desert further out. Many of the world’s big hot deserts lie close to the tropics: the Sahara straddles the Tropic of Cancer, and the Atacama and much of Australia’s desert lie near the Tropic of Capricorn. Countries crossed by the Tropic of Capricorn include Chile, Brazil, Namibia, South Africa and Australia, and countries crossed by the Tropic of Cancer include Mexico, Algeria, Egypt, Saudi Arabia, India and China. Between the tropics and the polar circles is the temperate zone, with mild, changeable weather and seasons, where the UK lies. Beyond the polar circles are cold tundra and ice. Height matters as well as latitude, so even mountains near the Equator can have snow on top.

Children practise finding the four lines on a globe or atlas, naming countries they cross, and linking each zone to the climate and vegetation they expect. Schools choose which countries and examples to use. The topic often connects to work on latitude, the Equator and time zones, and to later study of weather and climate in secondary school.

Words your child will hear

Tropics: The hot region between the Tropic of Cancer and the Tropic of Capricorn.
Tropic of Cancer: The line of latitude about 23.5° north of the Equator.
Tropic of Capricorn: The line of latitude about 23.5° south of the Equator.
Arctic and Antarctic Circles: Lines of latitude at about 66.5° north and south. The polar regions lie beyond them.
Axis: The imaginary line through the Earth from pole to pole, around which it spins.
Climate zone: A large region with a similar pattern of temperature and rainfall, such as tropical or polar.
Biome: A large natural community of plants and animals, such as rainforest or tundra.

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)
Describe and understand key aspects of physical geography, including: climate zones, biomes and vegetation belts, rivers, mountains, volcanoes and earthquakes, and the water cycle

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

Try it: explaining the midnight sun

Tromsø in northern Norway is at about 69.6° N. Explain why the Sun does not set there for weeks in June.

Compare the latitude with the Arctic Circle. Tromsø is at about 69.6° N and the Arctic Circle is at 66.5° N, so Tromsø is inside the Arctic Circle.
Recall the tilt. The Earth’s axis is tilted by about 23.5°. In June, the northern end of the axis leans towards the Sun.
Think about the Earth turning. As the Earth spins once in 24 hours, places inside the Arctic Circle stay in sunlight all the way round, so the Sun never dips below the horizon.
State the result. Around the June solstice, Tromsø has the midnight sun for weeks, with daylight at midnight.
Check the opposite season. In December the northern end of the axis leans away from the Sun, so Tromsø has weeks when the Sun does not rise above the horizon, although there is some twilight around midday.

Tromsø is inside the Arctic Circle. In June the northern half of the Earth is tilted towards the Sun, so as the Earth spins the town stays in sunlight and the Sun does not set for weeks. In December the tilt is the other way, and the Sun does not rise.

Common mistakes and how to help

Thinking seasons happen because the Earth is nearer or further from the Sun

It seems natural that being closer means hotter, and many children have heard this idea.

What helps: Explain that the tilt of the Earth’s axis matters. Use a torch and a ball to show how one half gets more direct light at a time. Seasons are opposite in the north and the south.

Believing the Equator or the tropics are lines you could see, or that they are always the hottest places

On a map the lines are drawn like borders, so they look like real features, and children hear that the tropics are hot and assume everywhere inside them is.

What helps: Remind your child that the lines are imaginary and help us describe position. Climate depends on height, nearness to the sea and winds too, so some tropical mountains have snow.

Mixing up the Arctic and the Antarctic

The two words look and sound almost identical, and both are cold and icy.

What helps: Point out that “Antarctic” means opposite the Arctic. Polar bears live in the Arctic, in the north, while penguins live mainly in the south.

Thinking it is dark all winter and light all summer everywhere

Children hear stories about the midnight sun and the polar night and assume the whole country, or the whole world, has them.

What helps: Show that this only happens inside the polar circles. The UK has long summer days and short winter days, but the Sun rises and sets every day.

How to help at home

Torch and ball. In a darkened room, shine a torch on a ball or a globe held at a tilt. Move the ball around the torch while keeping the tilt pointing the same way and watch which half gets more light.
Track daylight. Find the sunrise and sunset times in a weather forecast every week for a few weeks. Does the day get longer or shorter, and what happens in the opposite season?
Find the four lines. On a globe or atlas, find the Equator, the Tropics and the polar circles, and list the countries each one crosses. Which of them has your family visited or heard of?
Zone detectives. Choose five places from different parts of the world and decide whether each is in the tropics, the temperate zone or a polar region. Check against an atlas and think about what the weather might be like.

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