Making Clear Ice Cubes

Have you ever tried to make clear ice cubes?  No?  Then check out any ice cubes in your freezer.  Try freezing a class of tap water.  You'll find that finding and/or making clear ice cubes is very difficult.  Although you don't see them, water out of the tap contains small air bubbles.  As the water changes phase into ice, the bubbles expand and give the ice cube a cloudy appearance, as shown in the "cloudy" ice cube from my own freezer.

You probably don't have a need of making clear ice cubes, but it is possible to do.  Begin by boiling a pot of water.  The boiling process removes air bubbles in the water.  After boiling the water, very slowly poor the water into a freezer safe container.  It's important to pour the water very slowly along the side of the container.  Pouring too quickly or jostling the container will re-introduce air into the water.  Seal the container and place it in the freezer for a few hours.  Once the water has frozen, you should see a more clear ice cube.

Although not perfect, the picture above is our attempt to make a clear ice cube.  The container on the right is standard tap water.  The container on the left is frozen water after the boiling process.  The picture doesn't do this experiment justice, but the ice on the left is more clear than the standard tap water ice on the right.

Give it a try!