What is isostasy?

Imagine Earth’s crust is like a giant sponge floating on a soft jelly-like layer beneath it, that's isostasy in action!

Think of the Earth as having two layers: a top layer, called the crust, and a softer bottom layer, called the mantle. The crust is like a sponge floating on top of the jelly-like mantle.

If you put more weight on one part of the sponge, like stacking blocks on it, that part sinks a little into the jelly. But if you take away some weight, like removing blocks, that part floats up again. This balancing act is called isostasy.

Mountains are like big, heavy blocks on the sponge, they make that part of the Earth sink a little. Oceans are like shallow parts of the sponge, they float higher because there’s less weight pressing down.

So, when Earth moves or changes, like when ice sheets melt or mountains grow, the crust adjusts, sinking or rising like a sponge in a bath tub!