Snow at the poles

[Francis Asis]

With all the snow about lately it got me wondering.
At the poles theres loads of snow and its always cold. So with no heat melting the snow does that mean that the snow is the same snow that's always been there and always will be?

[MarkRae]

Yep. That's why scientists drill down into the snow and extract a "tube" of it. They then use this to analyse the levels of various elements and examine if these have changed over time...

[Francis Asis]

Thanks for both answers.
Zac - you could be right.
Mark - that's amazing. i've learned something today.

[MarkRae]

http://en.wikipedia.org/wiki/Ice_core

[gen2]

Some parts of Antarctica are really arid deserts so yes, the snow there is the same snow all the time since no new snow falls.

Elsewhere (on land) the snow accumulates and gradually flows downhill as glaciers to the sea.

Snow that falls on water-ice weighs it down so that it sinks deeper into the water where it is warmer. The ice melts off the bottom as more snow/ice accumulates on the top.