How do bubbles blow?

- Bubbles form when a thin film of soapy water or a surfactant solution is stretched and filled with air. Soap or surfactants reduce the surface tension of water, allowing it to stretch more easily and form bubbles.

2. Surface Tension:

- Surface tension is the force that pulls the surface of a liquid together, creating a "skin." In the case of soap or surfactant solution, the surface tension is lowered, reducing the force that pulls the water droplets together.

3. Air Trapping:

- When a bubble-blowing wand or a similar tool is dipped in the soapy solution and moved through the air, a thin film of soap solution forms on the surface. As the wand moves, air is trapped inside this film, creating a bubble.

4. Spherical Shape:

- The spherical shape of bubbles is a result of the surface tension of the soap film. The surface of a sphere has the lowest surface area for a given volume, so it is the most energetically favorable shape for a bubble to adopt.

5. Expansion and Burst:

- As a bubble floats through the air, it gradually expands due to the internal air pressure. However, the soap film has limited elasticity, and as the bubble grows larger, the surface tension can no longer withstand the internal pressure. Eventually, the bubble bursts, releasing the trapped air.

Factors Affecting Bubble Formation:

- Soap or Surfactant Concentration: Higher concentration of soap or surfactant enhances bubble formation by lowering the surface tension more effectively.

- Airflow: Bubbles form best in still air. Strong winds can disrupt the formation and cause bubbles to pop prematurely.

- Temperature and Humidity: Temperature and humidity can affect the evaporation rate of the water in the soap film. Bubbles tend to evaporate faster in warm and dry environments, causing them to burst more quickly.

In summary, bubbles blow due to the reduction in surface tension when soap or surfactants are introduced into water, allowing a film of soapy water to stretch and trap air, forming spherical shapes that eventually expand and burst.