It’s happened to all of us at some point squeeze an almost empty ketchup bottle and watch as its content explodes, leaving everything around lost. It happened to us, but we may not have asked ourselves why. However, a group of scientists from Oxford University Yes, you have asked yourself this question and even performed calculations to answer it.
It is important to indicate that the results of your study have already been published. only as a preprint. This means that they have not yet passed the required revision for publication. However, after receiving this feedback, they presented their work at the conference. Department of Hydrodynamics American Physical Society.
While this should be treated with caution, it’s interesting how they used science to explain something so mundane. And look for solutions as they showed what we can do as users or even what improvements could be introduced ketchup producers so that this doesn’t happen. Okay, it’s not vital research, but at least it’s interesting. Science is too.
Ketchup and fluid physics
When we press ketchup bottleseveral forces intervene, but two are chiefly involved in this phenomenon.
On the one hand, the air in the upper part of the vessel is compressed like a spring, pushing fluid under. Meanwhile, this downward force is counteracted by the attraction of the ketchup to the walls of the container. And what happens if there is not enough ketchup? Well, basically, it’s not enough to contain the downward force, so compressing the air causes the sauce to slosh out with an explosion.
Nothing happens: there is a solution
It should be noted that this study was not conducted with a ketchup bottle. In fact, its authors conducted a series of experiments injecting air from a syringe into an oil-filled capillary tube. Thus, they wanted to find out why a smooth flow of liquid can suddenly splatter like a sprinkler.
Chris McMinn, one of the authors of the study, explains in a statement what is happening and how the problem can be addressed. “You need to compress the air to create the driving force to move the fluid, and as the fluid flows, the viscosity resistance decreases because there is less and less fluid left,” he notes. “At the same time, the liquid outlet creates more space for air to expand in the tube, which reduces driving force with time”.
Therefore, the key is in gently squeezeto prevent too much compression of the air. In addition, they believe that if ketchup manufacturers large nozzles, part of the problem would also be solved, since the viscous resistance would decrease. And it would be solved even more if valves they have many such containers. It is true that they are very useful to avoid spills. However, they must be compressed before the ketchup can come out, so the air is compressed even more and splattering increases.
To prevent this from happening, McMinn and his team recommend: remove the lid when the ketchup is low. In this way, the space is increased so that the ketchup can flow freely and there is no need to make so much effort. As the Oxford University professor himself notes, we already guessed this intuitively, but now it is confirmed by mathematics. Even if the study hasn’t been reviewed yet, we can at least open the lid by thinking about the physics of what we’re doing.
Source: Hiper Textual
