Why Does Ice Float? Unlocking Water's Mysteries | BBC Earth Science?

Ice floats because it’s lighter than the water around it, just like a bubble in a glass of soda is lighter than the liquid.

Imagine you have a cup full of water. Now, put that water into the freezer and watch it turn into ice. Even though it's now solid, it takes up more space, kind of like when you blow up a balloon and it gets bigger.

When water freezes, it becomes ice. But instead of getting squished together, the molecules in ice spread out a little bit, making it less dense than liquid water. Because it’s not as heavy for its size, ice floats on top, just like how a feather floats on water while a stone sinks.

This is why lakes and ponds don’t freeze completely from the bottom up, the ice forms on top. If ice were heavier than water, it would sink, and eventually all the water would turn to ice!

So next time you see an ice cube in your drink, remember: it’s not just cold, it’s also lighter than the liquid around it!