Everyone loves bubbles*. We love to blow them, to observe them, and even to drink them in our sodas*. Bubbles are almost magical*, but why are bubbles round?

　　Bubbles and balloons have a lot in common. Scientists refer to them as “minimal surface structures*.” This means that they always hold the gas or liquid inside of them with the least possible surface area. The geometric form* with the least surface area for any given volume* is always a sphere*, not a pyramid* or a cube* or any other form.

　　An amazing exception* to the rule! (Not really.) When a normally round bubble is surrounded by other bubbles, it can be made to take on a seemingly odd shape. Here, a bubble filled with smoke to make it more visible* is surrounded by six other bubbles. It appears to be a bubble cube! If the surrounding bubbles are popped*, though, the bubble in the center reverts* to its natural “round” shape.

　　One challenge in bubble blowing is to make a bubble that can last longer than any other bubble blown.

　　One way to increase your ability to do this is to add a substance to the bubble solution* that will keep the water in the solution from evaporating*. Water evaporates fairly quickly, and if you can stop the evaporation process, your bubble will last longer.

　　Now that you understand a little more about bubbles, it is time to go and mix up some bubble solution and try to blow the largest and longest-lasting bubbles you can. You are never too old to enjoy bubbles and never too young to learn why bubbles are round.

　　(SD-Agencies)

　　(Difficulty: senior)