Read

The Arctic Circle lies at about 66.5° north and the Antarctic Circle at 66.5° south. Inside them, the Sun stays up for at least one whole day in summer and does not rise for at least one day in winter. At the North Pole the Sun sets around 21 September and does not rise again until around 21 March.

The poles are cold mainly because sunlight reaches them at a low, slanting angle. Snow and sea ice are white and reflect far more sunlight back to space than dark ocean water does.

The Arctic is an ocean mostly surrounded by land. Antarctica is a continent surrounded by ocean, covered by an ice sheet up to 4.8 km thick that holds about 90% of the world's fresh water found at the surface. The lowest temperature ever recorded on Earth, −89 °C, was measured at Vostok station in Antarctica.

Experiment: Does huddling keep you warm? A fair test

1. Fill all seven bottles with the same amount of warm tap water from the same jug.
2. Measure and write down the starting temperature.
3. Stand six bottles in a tight ring around the seventh and hold them together with a rubber band: this is the huddle. Put a thermometer in the middle bottle.
4. Stand one more bottle on its own, a hand's width away from the huddle, with the second thermometer. (If you only have seven bottles, take one from the ring and use a smaller ring of five.)
5. Leave everything in the same cool place for 20 minutes.
6. Read both thermometers. Which bottle lost less heat?

Bottle	Temperature at start (°C)	After 20 minutes (°C)	Drop (°C)
Middle of the huddle	Prediction
On its own	Prediction

Questions

1. Give two reasons why the polar regions are so cold.

2. Write three differences between the Arctic and Antarctica.

3. In the huddle test, what did you change, what did you measure and what did you keep the same?

4. Antarctic sea ice grows from about 2.8 to about 18.6 million km² each year. How much new sea ice is that?

Sources for every fact on this sheet: echoesof.science/school/polar-regions/sources/

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