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Do bubbles last longer in cold weather or hot weather? Why? — A, Alpharetta, Georgia

bubblesBubbles last longer in cold weather because their lifetimes are limited by evaporation. The water and other liquids in a bubble gradually evaporate and the bubble eventually loses its stability and pops.

If you watch a soap bubble carefully, you'll see that its colors change with time. These colors are caused by interference effects in the light waves as they reflect from the soap film's outer and inner surfaces. The tiny distance separating those two surfaces gets smaller as the bubble loses molecules and that length change affects the bubble's colors.

At a lower temperature, the rate at which molecules leave a soap bubble decreases and the bubble lasts longer. High humidity should also help preserve the bubble because molecules can also return to the bubble from moist air. My favorite time to blow soap bubbles is on a bitter cold but calm winter day when the bubbles freeze solid and settle to the ground as intact spheres. They can then last for many minutes before they finally lose enough molecules to let them tear. They then collapse slowly and gracefully, like tents settling after you remove their support poles.

Answered by Lou A. Bloomfield of the University of Virginia