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Bubble Geometry: Why Are Bubbles Round?

toby building bubble shapes

Why are bubbles round? What happens if you dip a non-round object into a bucket of bubble juice? Can you blow a triangular bubble? Let’s find out! Join Toby in this fun #ScienceWorksOnline activity.

The Science of Round Bubbles

Bubbles can stretch and look like long worms or distorted balloons while they are being formed. But once a bubble is sealed and removed from the wand, the tension in the bubble shrinks it to the smallest possible shape for the volume of air inside of it. That’s a sphere, which is the familiar round shape we see when bubbles float through the air. Compared to any other shape, a sphere has the least surface area for the volume of air inside.

So even if Toby blows air through a triangle-shaped bubble film, the resulting bubble is a round sphere — not a triangle. Amazing, right?

Try Our Favorite Bubble Recipe

Mix up your own batch of super bubble juice and try some experiments of your own! What happens when you use different materials and shapes for your bubble wand? Make some predictions and test your own ideas!