Bubbles

For generations, bubbles have sparked the curiosity and imagination of children and adults alike. They love to blow them, pop them and fit inside them. Bubbles aren't just for entertainment; they are the crisp effervescence in our sodas and sparkling water, and some doctors are even using microscopic bubbles to deliver medicine more effectively. Whether for entertainment or scientific study, scientists have been turning their attention to why bubbles pop. For many years, it was believed that bubbles popped because of gravity. When a hole is poked in a bubble, the hole expands over time, and the bubble collapses. Because the hole wasn't growing as fast as the bubble was shrinking, scientists chalked it up to gravity. There are two primary reasons a bubble will pop. First, because it gets poked, as we mentioned above. When a bubble is poked, a hole forms and surface tension causes the molecules to shrink so quickly that the bubble flattens or bursts and the water escapes as tiny droplets. The second reason a bubble pops is because its water evaporates. Because the film around the bubbles contains water, it will evaporate over time. Suppose a bubble manages to escape the pursuit of a stick-wielding child. In that case, it will eventually pop once the water evaporates, i.e., it turns into a gas and breaks those molecular bonds that create the surface tension. The more viscous a solution, the longer it takes for water to evaporate. Water also evaporates faster when the air temperature is higher, so bubbles pop more quickly on a warm day than on a cooler one.