Monday, August 31, 2015

Water to Ice = Expansion

Here's an inadvertent science experiment we did at home that you can also do in a controlled way.  We like to put a sports bottle of water in the freezer to take out when frozen to soccer games and soccer practices.  On hot days, we have a second bottle that started as ice, but melts into cool water a couple of hours later when we still want cool water to drink.  However, one must be careful when doing this because water expands as it changes phase into ice.  One can't fill a sealed bottle to the top with water.  Doing so allows no room for the water to expand as it transitions to ice.  The water WILL expand one way or another.  In our case, there was nowhere for the expanding ice to go, so it cracked the container, as shown below.

You can also see that the bottom of the bottle is rounded.  The container gave a little bit, but the ice expanded far too much and the container cracked.  If a can of pop gets too cold, the pop inside (mostly water) will expand, and the can will pop open, spraying pop everywhere!  

I recommend doing this as a science experiment to show you kids that water does expand when it becomes ice.  Use a bottle you have no use for again and test it out.  How long does it take to pop?  

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