What is Regelation?

Regelation is when ice can melt and freeze again just by being squeezed or pressed.

Imagine you have a block of ice, like the kind that makes your popsicle cold. Now picture pressing it between two heavy books, like when you try to squish a stack of papers really hard. The pressure from the books makes the ice melt into water, even if it's not warm outside. But once you take away the pressure, the water freezes again into ice! It’s like the ice is doing a little dance between being solid and liquid.

You can see regelation in action when you make a snowball. When you press the snow together, the pressure makes some of the snow melt, but then it freezes again as you keep rolling it, that’s how your snowball gets bigger and stays firm!

Or think about ice skates: when you skate on ice, the pressure from your blade melts a thin layer of ice underneath, making it easier to glide. Then, when the pressure is gone, that water freezes again, just like regelation!