Slowly, pour some water from the second glass into the first glass until it is very full and the water forms a dome above the rim of the first glass. Set the second glass of water aside.

To quantitatively compare the two breakup modes, several key statistics of the bubble geometry, orientation, and breakup time, obtained from the 3D shape reconstruction, are provided. In Fig. 2b, the probability density functions (PDFs) of the bubble aspect ratio α, obtained from the 3D reconstructed bubble geometries from 6 ms before to the moment of breakup, for both breakup modes are illustrated. It is evident that the primary breakups typically feature a larger α compared with the secondary breakups. Furthermore, Fig. 2c shows the PDF of the bubble orientation, indicated by the angle between the bubble semi-major axis and the z-axis ( θ), suggesting that bubbles have preferential alignment with the z-axis during the primary breakup, while the distribution of θ for the secondary breakup is wider due to the disturbances from the surrounding turbulence. The third statistics that can be used to distinguish the two breakup modes is the breakup timescale t c, which is defined as the time delay between the start time to the breakup instant. Note that the start time is not chosen immediately after the previous breakup, but at the minimum bubble aspect ratio closest to the breakup moment, when the bubble begins to be deformed by an eddy that will eventually break it. Figure 2d shows the PDF of t c for the two breakup modes. The secondary breakup skews significantly more towards a smaller t c compared with the primary breakup. These three statistical quantities show a consistent picture as the two examples in Fig. 2a. Another interesting aspect of the nucleation of bubbles in the proximity of a boundary resides in their jetting dynamics. Laser-induced bubbles produced under different boundary conditions have been widely studied, both experimentally and numerically. Perhaps the case that got the most attention is the one of a bubble collapsing in the proximity of a boundary of large extent, e.g. a solid boundary (Plesset & Chapman Reference Plesset and Chapman1971; Lauterborn & Bolle Reference Lauterborn and Bolle1975; Blake et al. Reference Blake, Keen, Tong and Wilson1999; Brujan et al. Reference Brujan, Keen, Vogel and Blake2002; Lindau & Lauterborn Reference Lindau and Lauterborn2003; Yang, Wang & Keat Reference Yang, Wang and Keat2013; Lechner et al. Reference Lechner, Koch, Lauterborn and Mettin2017; Gonzalez-Avila, Denner & Ohl Reference Gonzalez-Avila, Denner and Ohl2021), an elastic boundary (Brujan et al. Reference Brujan, Nahen, Schmidt and Vogel2001; Rosselló & Ohl Reference Rosselló and Ohl2022) or a free surface (Koukouvinis et al. Reference Koukouvinis, Gavaises, Supponen and Farhat2016; Li et al. Reference Li, Zhang, Wang, Li and Liu2019 c; Bempedelis et al. Reference Bempedelis, Zhou, Andersson and Ventikos2021; Rosselló, Reese & Ohl Reference Rosselló, Reese and Ohl2022). In real-world conditions the boundary is of finite extent and the cavity may be spuriously affected by more than a single boundary (for instance, the walls of a container or the liquid free surface), exerting a considerable influence on the direction of the jetting (Kiyama et al. Reference Kiyama, Shimazaki, Gordillo and Tagawa2021; Andrews & Peters Reference Andrews and Peters2022). Touch the straw to the lid and blow a bubble on the lid. Slowly, pull the straw all of the way out of the bubble.Dip a straw into the container of Homemade Bubble Solution getting half of the straw completely wet. Using a second pipe cleaner, fold it in half and loop it around one sdie of the other pipe cleaner square. Twist the ends to make a handle.

After the primary breakup, based on the KH framework, the daughter bubbles should become harder to break because their sizes are smaller and the bubble-scale eddies have weakened, yet it is surprising to find that the daughter bubble experiences a more violent breakup, as shown in the second case of Fig. 2a. This more violent breakup is referred to as the secondary breakup hereafter. The secondary breakups have three features: (i) a rough bubble interface with large local curvatures; (ii) complicated deformation along non-persistent directions; and (iii) short breakup time. The secondary breakup occurs within 5.1 ms, which is much smaller than 32.1 ms for the primary breakup. The two breakup modes are always correlated with the bubble breakup locations. In practice, a critical height at y c = −51 mm (corresponding to the vortex ring bottom location at t = 0.10 s after their collision) was used to separate the two breakup modes (primary y> y c; secondary y< y c). More discussions of this separation criterion can be found in Supplementary Information. The difference in the two breakup modes can be linked to the distinct breakup mechanisms involved. For the primary breakup, the large-scale vortex entrains the bubble towards its center—a local pressure minimum. For a bubble with a size close to the vortex diameter, as it reaches the vortex center, it experiences a pressure gradient that tends to compress it along the radial direction and extend it along the z-axis. Secondary breakup is more irregular, driven by a turbulent cloud filled with sub-bubble scale eddies. Bubbles break without significant elongation because the process is disrupted and accelerated by these eddies with smaller timescales, which also explains the observed difference in breakup time t c. where λ 3 (the largest compression rate) is the smallest eigenvalue of \({\widetilde{S}}_{ij}\), and ω is the vorticity magnitude. The new definition of the two Weber numbers extends the original one-dimensional version in the KH framework to emphasize the contributions from the 3D straining and rotational flows. Nevertheless, the key assumption in the KH framework that the only relevant length scale is the bubble size is still applied here.The KH framework implies that bubbles with larger Weber numbers tend to break more easily. If it were right, we should expect a more violent primary breakup. However, the observations suggested otherwise, which clearly refute the key hypothesis in the KH framework. For the secondary breakup, although the eddy of the bubble size is much weaker, many sub-bubble-scale eddies begin to emerge. To demonstrate their appearance, we apply a high-pass rolling-average spatial filter with a filter length l = 3 mm (which is selected to be close to the bubble mean diameter) to the velocity field. The residual fluctuation velocity u < and its variance \(\langle {u}_{\,{ < }\,} The dynamics of jetting bubbles inside drops or curved free surfaces have not been extensively explored. Recently, we have reported experimental and numerical results on the formation of a jetting bubble in the proximity of a curved free boundary, given by the hemispherical top of a water column or a drop sitting on a solid plate (Rosselló et al. Reference Rosselló, Reese and Ohl2022). As a natural extension of that work, we now present a study on the jet formation during the collapse of laser-induced bubbles inside a falling drop. This is a particularly interesting case as the bubble is surrounded entirely by a free boundary. From an experimental point, the intrinsic curvature of the liquid surface offers a very clear view into the bubble's interior.

We emphasize that the primary breakup follows the key hypothesis made in the classical KH framework, in which a bubble is assumed to be broken by a clean and isolated vortex filament with a size close to the bubble diameter. However, most bubble breakups observed in fully developed turbulence are closer to the secondary case, where the contribution from a cloud of smaller eddies cannot be ignored. Bubble breakup mechanism A very popular game that kids play is the bubble-blowing competition. The aim of this game is blowing the largest bubble. You can also twist it to add more fun. For example, see who can produce the most bubbles at one go. Once the bubble was entrained into one of the vortices at the collision point, it was carried downwards by the flow. During this process, we observed two distinct bubble breakup modes, the examples of which are shown in Fig. 2a. For the first case, a bubble was deformed consistently along the z-axis until the moment of breakup. This process is relatively slow, and the bubble’s interface seems to be smooth throughout the entire process, similar to what was observed in the linear-extensional flows 13, 14. For the rest of the paper, this type of breakup is referred to as the primary breakup as it occurs first and always before the moment when the two vortex rings break down to a turbulent cloud. If you're ready for some popping fun, Arkadium's Bubble Shooter free online game is here to deliver a thrilling and addictive experience! The key hypothesis in the KH framework is that, in turbulence, bubbles/drops with diameter D are broken by eddies of the same size and the contribution from sub-bubble scale eddies is negligible. The most important dimensionless number based on D is thus the Weber number. The fundamental challenge associated with this key hypothesis is not about its correctness but its falsifiability. For fully-developed turbulence, eddies of many length scales are present at the same time. In these situations, bubbles always encounter eddies of various sizes, so it is extremely difficult to disentangle them cleanly 10, not to mention establishing their roles in bubble breakup. Therefore, there has been no direct experimental evidence so far to either support or refute this hypothesis.

Creative Play

If you’re looking for a bubble game that’s easy to play for kids, Candy Bubble is a great choice for younger players. The levels feature straight-forward instructions and a line to indicate the path of the bubbles you are shooting. More Bubble Games