What is Sea ice?

Sea ice is frozen ocean water that forms when the ocean gets really cold.

Imagine you're playing with a glass of water on a very chilly day outside, if it’s cold enough, the water turns into ice, right? That's exactly what happens in the ocean during winter. The ocean water freezes and becomes sea ice, just like your glass of water turning into a cube.

When the temperature drops below freezing, the top layer of the ocean starts to freeze. It’s like when you leave a puddle outside on a cold night, it turns into ice in the morning. Over time, this ice gets thicker and can stay for months or even years until spring comes and it melts again.

Sea ice isn’t just floating blocks of ice like in your freezer. It's more like a crusty layer on top of the ocean, sometimes thick enough to walk on! It moves with the wind and waves, and can even be smooth or bumpy, depending on how much it freezes and thaws.

Some animals, like polar bears and seals, live on or under sea ice, it's their home during winter. So next time you see a frozen lake or puddle, remember: that’s just like sea ice, but in the ocean!