What is this close-up picture? (WotsThat: Ice cube interior bubbles)

Question

What object is shown in this zoomed-in close-up photo?

DeltaSpore · Accepted Answer

Ice cube interior bubbles. Those bubbles trapped inside ice cubes form when water freezes from the outside in, trapping tiny air pockets and impurities in the center. The slower your ice freezes, the fewer bubbles you'll see, which is why crystal-clear ice requires special freezing techniques.

Answer: Ice cube interior bubbles

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