Why Soap Bubbles Are Round

Look at a soap bubble. What shape is it? It is round. Every soap bubble is round. Why?

The answer is science. The science is surface tension.

A soap bubble has three parts: water, soap, and air. Air is inside. Water and soap make a thin skin outside.

Water likes to hold on to water. Water drops pull together. This pull is surface tension.

Surface tension makes a tight skin. The skin pulls the water into a small shape. What is the smallest shape? A sphere. A sphere is a round ball.

Air pushes out from the inside. The skin pulls in from the outside. Both forces work together. The air pushes equally in all directions. The skin pulls equally in all directions. This makes the bubble round.

If you blow a bubble, it might start funny. But it quickly becomes round. The skin finds the best balance.

Soap makes bubbles better than plain water. Plain water has high surface tension. It breaks fast. Soap makes the water skin stretchy. It holds the air longer.

Next time you blow bubbles, look closely. Are they all round?

Why do you think soap bubbles pop?