This time, Virginia Tech researcher Jonathan Poliko and his colleagues studied the heat transfer process that drives the freezing of soap bubbles. They placed soap bubbles on a cold surface at different ambient temperatures and recorded the freezing process. They observed two different freezing mechanisms, depending on the temperature.
When the surrounding temperature is the same as the soap bubble temperature, freezing starts at the bottom of the soap bubble and creates a "Maragoni flow" (liquid flows from where the surface tension is low to where the surface tension is high), causing ice crystals to break away from the frozen interface and spin around the soap bubble like snowflakes inside a snow globe. Then, as the ice crystals grow and merge, the soap bubbles freeze completely. But when the surrounding temperature is room temperature, the frozen interface slowly expands upward and eventually stops in the middle of the soap bubble -- because of poor conduction. This semi-frozen bubble will remain in equilibrium until the liquid dome finally collapses.
The discovery could help physicists better understand heat transfer, the researchers said.
Cochinita Journal
Decrypt the physical mechanism of "Snow globe Effect"
A physics paper published Wednesday in the British journal Nature Communications reveals how soap bubbles freeze into beautiful spheres of ice crystals, a previously undiscovered mechanism that gives rise to the "snowball-globe effect."
When a soap bubble freezes under certain conditions, a large number of growing ice crystals are observed hovering inside it, reminiscent of a snow globe -- a hollow glass sphere or dome with a bottom that holds ornaments and "snowflakes" in place. Until now, however, no research had investigated the physical mechanism behind this phenomenon or how soap bubbles freeze. wholesale snow globes are available here.
This time, Virginia Tech researcher Jonathan Poliko and his colleagues studied the heat transfer process that drives the freezing of soap bubbles. They placed soap bubbles on a cold surface at different ambient temperatures and recorded the freezing process. They observed two different freezing mechanisms, depending on the temperature.
When the surrounding temperature is the same as the soap bubble temperature, freezing starts at the bottom of the soap bubble and creates a "Maragoni flow" (liquid flows from where the surface tension is low to where the surface tension is high), causing ice crystals to break away from the frozen interface and spin around the soap bubble like snowflakes inside a snow globe. Then, as the ice crystals grow and merge, the soap bubbles freeze completely. But when the surrounding temperature is room temperature, the frozen interface slowly expands upward and eventually stops in the middle of the soap bubble -- because of poor conduction. This semi-frozen bubble will remain in equilibrium until the liquid dome finally collapses.
The discovery could help physicists better understand heat transfer, the researchers said.
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This time, Virginia Tech researcher Jonathan Poliko and his colleagues studied the heat transfer process that drives the freezing of soap bubbles. They placed soap bubbles on a cold surface at different ambient temperatures and recorded the freezing process. They observed two different freezing mechanisms, depending on the temperature.
When the surrounding temperature is the same as the soap bubble temperature, freezing starts at the bottom of the soap bubble and creates a "Maragoni flow" (liquid flows from where the surface tension is low to where the surface tension is high), causing ice crystals to break away from the frozen interface and spin around the soap bubble like snowflakes inside a snow globe. Then, as the ice crystals grow and merge, the soap bubbles freeze completely. But when the surrounding temperature is room temperature, the frozen interface slowly expands upward and eventually stops in the middle of the soap bubble -- because of poor conduction. This semi-frozen bubble will remain in equilibrium until the liquid dome finally collapses.
The discovery could help physicists better understand heat transfer, the researchers said.