science / Real
Does water expand when it freezes?
Yes. Ice is less dense than liquid water, which is why it floats.
ICE FLOATS
The Claim
Water expands as it freezes into ice.
The Answer
The USGS Water Science School explains that water behaves unusually: it expands when it freezes. That lower density makes ice float on liquid water.
Why This Is Surprising
It sounds like the kind of claim that races around social feeds without context. The source trail matters because the best version of the wonder is the verified one.
How We Checked It
We looked for an authoritative primary source, checked the wording against at least one credible secondary source when available, and recorded the last review date.