What is the difference between liquid bubble and air bubble?
Bubbles are fascinating, intriguing and mesmerising - whether it is floating in the air or in the water, they never cease to grab our attention. They soft and delicate spheres that form effortlessly in the environment around us, yet their structures and properties are complex and intricate. But, did you know that there is a fundamental difference between "liquid bubble" and "air bubble"?
The Structure of Liquid Bubble
Let''s begin by understanding the structure of liquid bubble. A liquid bubble is formed when a relatively thin layer of liquid holds air within it. This thin layer is called a "surface film" or "surface tension". The surface tension of a liquid is due to the attraction between the molecules at the surface of the liquid - they are more strongly attracted to each other than to the air or gas above them. This attraction creates a "skin" or "membrane" of liquid just above the air or gas.
As the air trapped inside the surface film expands, the surface of the bubble grows larger, creating a spherical shape. The strength of the surface film is vital for maintaining the shape of the bubble. However, the surface of a liquid bubble is continually breaking and reforming, causing the bubble to eventually burst.
The Structure of Air Bubble
On the other hand, an air bubble is created when air or any other gas is trapped within a liquid medium. The air trapped within the liquid forms a spherical shape, which we commonly know as the "air bubble". Unlike a liquid bubble, an air bubble does not have a "skin" or "membrane" covering it.
However, the properties of the medium surrounding the air bubble play an important role in maintaining its shape. The surface tension of the medium allows it to hold the air bubble in place. The pressure of the surrounding liquid also affects the shape and size of the bubble. For instance, an increase in the pressure of the surrounding liquid can compress the size of the air bubble, while a decrease in the pressure can cause it to expand.
Properties of Liquid and Air Bubble
The properties of liquid and air bubbles differ significantly from one another. Some of them are discussed below:
Physical State
A liquid bubble is essentially a sphere of liquid enclosing a small volume of air. Thus, its physical state is primarily a liquid. On the other hand, an air bubble is a small volume of gas or air trapped within a liquid medium, making its physical state gaseous.
Transparency
Generally, liquid bubbles are transparent or translucent, depending on the transparency of the liquid medium. In contrast, air bubbles are mostly visible due to the presence of air confined within the liquid medium.
Density
Liquid bubbles are generally denser than air bubbles. Since liquid is heavier than air, it takes more force to create a liquid bubble than an air bubble.
Formation
Liquid bubbles form gradually as air is introduced into the liquid matrix. Air bubbles, on the other hand, can form spontaneously when tiny pockets of air are present in the liquid medium.
Surface Area
Liquid bubbles have greater surface area than air bubbles, due to their "skin" or "membrane" structure. The surface of a liquid bubble is constantly breaking and reforming, creating a larger surface area. Air bubbles, on the contrary, do not have a surface film, thus having a smaller surface area compared to liquid bubbles.
Summary
To summarise, the fundamental difference between liquid bubble and air bubble is the presence or absence of a skin/membrane. A liquid bubble is created when a layer of liquid holds air within it, whereas an air bubble is created when a gas or air is trapped within a liquid medium. Despite their contrasting properties, both liquid and air bubbles are fascinating marvels of nature, which never cease to pique our curiosity and engage our senses.
