Does water expand when it freezes?

United States
May 13, 2012 10:34am CST
I'm having trouble grasping the concept of water expanding when it freezes. If the water molecules are packing tighter and tighter to create a solid how does the ice take up more space. I need someone to give me a dumbed down answer that I can wrap my head around.
2 responses
@owlwings (38861)
• Cambridge, England
13 May 12
When water freezes, it becomes crystalline and the crystal matrix takes up more space than the unaligned free water molecules. There's a good illustrated explanation here: http://www.iapws.org/faq1/freeze.htm Actually, water is at its densest at 4°C. As it cools beyond that, it expands until it freezes.
1 person likes this
• United States
13 May 12
It's just so weird. You see it happen in the freezer, but to explain it. I thought the container was shrinking.
@wolveren (1568)
• Cebu, Philippines
14 May 12
Yes the molecules of water packs tighter, but as they bond together they form hexagons, which creates more space in between them than before. That is how the ice expands.
• United States
14 May 12
Is there a reason why water does this?