What causes some ice cubes to be white and some to be clear?


What causes some ice cubes to be white and some to be clear?

– Stacey Torvik, Yankton

Dear Stacey,

There is one main reason for why ice cubes appear to be cloudy after you take them out of the freezer: Water purity. If you were to go pour yourself a glass of water into a clear and clean glass, you would likely find that it is clear and clean. However, there are very tiny minerals and sediment that are harmless (most of the time, unless you have to boil your water). When water is in its liquid form it is hard to see these minerals to the naked eye, however they are the reasons for the cloudy look in your ice.

Things freeze from the outside in as the colder air gets to that first. Water free of minerals and impurities freezes first, and as that water freezes, entrapped air and minerals are moved out of the freezing ice toward the unfrozen center. Eventually the trapped air becomes frozen water with air bubbles which looks like cloudy ice.

Ice will be clear if there is a very low amount of impurities in the water or on how it is frozen. Obviously, if there are no impurities, there will be nothing pushed into the center and there will likely be no bubbles in the center. However, some ice cubes are made by making a smaller ice cubs and then adding more water slowly. The water freezes bit by bit and the entrapped air and minerals don’t freeze. This is how most of the ice you buy in stores is made.

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Categories: Weather-imported