**4. Conclusions**

Through observation of the phenomenon of bubbles crossing the water–air interface under cold-water model conditions, we deduced the following:


**Author Contributions:** Project Administration and Writing—Original Draft Preparation, H.Z.; Data Analysis, J.W.; Experiment and Investigation, W.Z.; Supervision, F.L.; Writing—Review & Editing, X.C., Formal Analysis and Methodology, M.X.

**Funding:** This research was funded by "The Fundamental Research Funds for the Central Universities, grant number FRF-TP-19-016A3", "The Guangxi Innovation-Driven Development Project, grant number AA18242042-1" and "The University in Guangdong Province Grant, grant number 2015KQNCX157".

**Conflicts of Interest:** The authors declare no conflicts of interest.

#### **References**


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