Bubbles: round and popping
Physics · Early Years · The School
Blowing bubbles
Dip a wand into soapy water. Blow through it, gently. A bubble grows, wobbling, and floats free into the air. Watch where it goes. Watch how it catches the light, with swirling colours across its surface. Blow too hard, and the bubble bursts before it can even leave the wand.
Always round
Try a square wand. Try a triangle wand. Try a star-shaped wand. Blow a bubble from each one. Every single bubble comes out round, whatever shape the wand was. The soapy film pulls itself into a ball shape the moment it leaves the wand. It never keeps the wand's own shape, not even for a second.
Why bubbles pop
A bubble is a very thin, stretched skin of soapy water, with air trapped inside. Touch it with a dry finger, and the skin breaks. It pops. Wet fingers are gentler on a bubble than dry ones. Bubbles also pop by themselves, once their thin skin dries out too much to hold together.
Dip a square wand in soapy water and blow. Round bubble. Dip a triangle wand and blow. Round bubble again. Dip a star-shaped wand. Still round. Dip a plain circle wand, the shape you might expect to match. Round bubble, exactly the same as all the others. Four very different wands. One single result, every time: a perfectly round bubble, floating away.