Blow up soap bubbles never fails to please one’s inner child, perhaps because bubbles are ephemeral in nature, bursting after only a few minutes. Now, French physicists have succeeded in creating “eternal bubbles” from plastic particles, glycerol and water. a new sheet of paper published in a magazine Physics review liquid. The longest bubble they built lasted for 465 days.
Bubbles have long fascinated physicists. For example, the French physicists in 2016 work out a theoretical model for the exact mechanism of how soap bubbles form when gas jets hit a soap film. The researchers found that bubbles only form above a certain rate, which in turn depends on the width of the airflow.
In 2018, we reported about how mathematicians at New York University’s Applied Mathematics Laboratory have refined the perfect bubble blowing method based on a series of experiments with thin soap films. The mathematicians concluded that it was best to use a round wand 1.5 inches (3.8 cm) in circumference and blow gently at a steady rate of 2.7 inches per second (6.9 cm/s). S). Blow at a higher speed and the bubbles will burst. If you use a smaller or larger wand, the same will happen.
And in 2020, Physicists determined that a key ingredient to creating giant bubbles is mixing polymers of different fiber lengths. That creates a soapy film that can stretched thin enough to create a giant bubble without bursting. The polymer fibers become entangled, like a clump of hair, forming longer strands that do not want to break. In the right combination, a polymer that allows the soap film to reach its ‘sweet spot’, is viscous but also stretchable — not so stretchy that it rips. Changing the length of the polymer fibers results in a stronger soap film.
Scientists are also interested in extending the life of the bubbles. Natural bubbles are spherical in shape: a volume of air enclosed in a very thin layer of liquid skin to isolate each bubble in the foam from neighboring bubbles. Bubbles are geometrically characterized by surface tension, a force resulting from molecular attraction. The larger the surface area, the more energy is required to maintain a certain shape, which is why the bubbles seek to assume the shape with the smallest surface area: a sphere.
However, most bubbles will burst within a few minutes in standard atmosphere. Over time, the pull of gravity gradually draws the liquid to the bottom, and at the same time, the liquid component also slowly evaporates. As the amount of liquid decreases, the “walls” of the bubbles become very thin, and the small bubbles in the foam coalesce to form larger bubbles. The combination of these two effects is called “roughing”. Adding some kind of surfactant keeps the surface tension from collapsing bubbles by strengthening the thin liquid film walls that separate them. But in the end the inevitable always happens.
In 2017, French physicists see that a spherical shell made of plastic microspheres that can store pressurized gas in an extremely small volume. Physicists refer to these objects as “gas marbles”. These objects are related to so-called liquid marbles — liquid droplets coated with liquid-repelling, microscopic particles that can be rolled around on a solid surface without breaking apart. While the mechanical properties of gas balls have been the subject of a number of studies, no one has yet conducted experiments to explore the lifespan of the marbles.
