Get smart curated videos delivered to your inbox.   SUBSCRIBE
The Kid Should See This

Why can water drops pass through a soap bubble?

Watch more with these video collections:

Filmed in slow motion by Science Luxembourg, water drops travel through a soap bubble, mostly without breaking it. How can this happen? A translation from French at science.lu:

To understand the phenomenon, it must first be understood that the envelope of the soap bubble consists mainly of water… A hundred superimposed soap bubble membranes would be more or less the thickness of a sheet of paper. Then, on either side of this layer, there are surfactant molecules, similar to those used in dishwashing liquid. These molecules have two ends: one hydrophilic (which mixes well with water) and the other hydrophobic (rejected by water). In the film covering the soap bubble, the hydrophilic end is oriented towards the water molecules and the hydrophobic end towards the air.

When a drop of water crosses the film of the soap bubble, it dilutes the water/surfactant mixture somewhat to its point of entry. Since the water molecules like to stick to each other, the drop does not destroy the thin layer of water and simply passes through it.

water drops in a soap bubble

Related bubbles on TKSST: How to make an inverted bubble, how to make geometric bubbles, and Coalescence Cascade: A water drop dances in slow motion.

Bonus video: How does bubble engineer Melody Yang make mind-blowing bubbles?

This Webby award-winning video collection exists to help teachers, librarians, and families spark kid wonder and curiosity. TKSST features smarter, more meaningful content than what's usually served up by YouTube's algorithms, and amplifies the creators who make that content.

Curated, kid-friendly, independently-published. Support this mission by becoming a sustaining member today.

🌈 Watch these videos next...

Why does water roll off a duck’s back?

Rion Nakaya

Why (and how) do spittlebugs make bubbles?

Rion Nakaya

What makes that fresh rain smell? MIT films rain drops to find out

Rion Nakaya

Un sedicesimo n°44, crushed plastic balloons on paper

Rion Nakaya

Three LEGO soap bubble machine ideas

Rion Nakaya

The Tenant (O Inquilino): The journey of a soap bubble

Rion Nakaya

The Bubble Artist: Su Chung Tai (蘇仲太)

Rion Nakaya

Sugiyama Brothers – The Happy Bubblemakers

Rion Nakaya

Stanford researchers solve the mystery of the dancing droplets

Rion Nakaya