Basic Geology Uncategorized

Guest Video: Why Does Ice Float?

When water freezes, it should be at its most dense and drop to the bottom like a rock. Instead, ice floats, and for a long time, scientists have not understood why that happens.

It takes a little science to see why this is a very good question instead of a no-brainer.

  • Matter gets denser as it cools down.
  • Light things float.
  • Dense things sink.

This is one reason why, for instance, hot magma rises through “cold” rock from a source of molten rock deep within Earth’s mantle. The hot stuff is more buoyant than the cold stuff.

To some extent water works this way, too (though at much lower temperatures, of course). Warm ocean currents circulate in the upper parts of the sea, above cold bottom currents.

When water freezes, it should be at its most dense and drop to the bottom like a rock.

Instead, ice floats.

Here’s a BBC presenter drawing magic circles in the air to show you why this happens.

Featured Image: Niekverlaan at Pixabay. Public domain.


About BJ Deming

After getting an associate's degree in forestry, I studied geology as an undergraduate back in the 1980s but went into medical transcription instead. It just worked out better for me. The Internet renewed my interest in geoscience as a hobby, and when I retired in 2014, I decided to write a book about cat evolution. That started a new career for me (enormous fun but not self-supporting yet). Right now, besides blogging I am finishing up the first two books in a self-published ebook series about the cat family and its history. Thanks for your interest!

0 comments on “Guest Video: Why Does Ice Float?

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Volcano News, Discussions, Chat and more


"The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it." - Terry Pratchett

The Road To Endeavour

Walking alongside Opportunity as she explores Endeavour...

chasing sabretooths

Join Mauricio Antón in his search for clues to restore ancient life

Modern Astronomy

Discoveries, Journeys & Milestones in Space Exploration


Posts mainly about volcanoes

Chaplin-Keaton-Lloyd film locations (and more)

by John Bengtson "the great detective of silent film locations" New York Times

Sliding Thought Blog

Washington's Landslide Blog

Mysteries & Conundrums

Exploring the Civil War-era landscape in the Fredericksburg & Spotsylvania region.

The Elements Unearthed

Our Discovery and Usage of the Chemical Elements

Inside the Eye

Official Blog of the National Hurricane Center

Keith Picot

Silence Is Golden

%d bloggers like this: