Why Do Bubbles Pop?

What You'll Learn

• A bubble is a thin skin of soapy water filled with air
• The skin has two layers of soap molecules with water between them
• Bubbles pop when the water in the skin evaporates or gets touched
• Dry fingers, dust, or wind can break the thin skin
• The soap makes the water stretchy enough to form a bubble

Words to Know

Bubble

A round pocket of air in soapy skin

"I blew a big bubble."

Soap

A substance that helps water stretch

"Soap makes bubbles possible."

Evaporate

When water turns into invisible vapor

"Water evaporated from the bubble skin."

Fragile

Easy to break

"The bubble skin is very fragile."

Check What You Learned

Fun Facts

• A soap bubble is a thin film of soapy water enclosing air

  Source: Scientific American

• The bubble film consists of two layers of soap molecules with a water layer between them

  Source: American Physical Society

• Soap reduces water's surface tension, allowing it to stretch into a bubble

  Source: APS

• Bubble films are only a few hundred nanometers thick, making them very fragile

  Source: Scientific American

• Bubbles pop when the film is punctured by contact with dry objects, dust, or wind

  Source: APS

• Water in the bubble film evaporates over time, thinning the film until it ruptures

  Source: Scientific American