What can we learn from the 'Dancing Raisin' science experiment, which can be easily observed by simply putting raisins in carbonated water?
Some scientific experiments require expensive equipment and large investments, but there are also experiments that anyone can easily do. Saverio Eric Spagnoli, a mathematics professor at the University of Wisconsin in the United States, explains the 'dancing raisin' that can be observed simply by putting raisins in carbonated water.
'Dancing' raisins − a simple kitchen experiment reveals how objects can extract energy from their environment and come to life
In collaboration with two students, Spagnoli published a paper in May 2024 on 'what kind of buoyancy and power are generated in supersaturated liquids such as carbonated water.' Supersaturation is a state in which the liquid contains more gas than it can hold, so in carbonated water, the gas that does not dissolve in the water comes out as bubbles. When the bottle is sealed, bubbles do not appear due to the high pressure, but when it is opened, the pressure decreases and carbon dioxide molecules escape into the surrounding air.
Because raisins with wrinkled surfaces are suitable as objects to be placed in carbonated water and observed to move, Spagnoli and his colleagues call this research and the phenomenon of objects moving in supersaturated liquids 'dancing raisins.' Regarding his research on dancing raisins, Spagnoli said, 'I came across this phenomenon by chance while playing in the kitchen with my daughter, and I couldn't help but explore it further.' In connection with the research, a movie of raisins actually dancing up and down in carbonated water was released on X (formerly Twitter), and it attracted so much attention that it was viewed more than 500,000 times in two days.
It turns out that sparkling water and raisins are *fascinating*. My daughter and I happened upon this effect playing together in the kitchen a long time ago, and I couldn't help but explore the system more deeply... 1/n https://t.co/wNBX7nnGJS pic.twitter.com/BVmVOeHvrP
— Saverio Spagnolie (@SaverioIV) September 13, 2023
According to Spagnoli, the carbonated water we all know is full of interesting physics. Air bubbles don't normally form naturally in liquids. Liquids are made up of molecules that tend to stick together, so the molecules at the boundaries of the liquid experience surface tension , which causes the molecules to attract each other and reduce their surface area. Air bubbles increase their surface area, so the surface tension and liquid pressure cause the bubbles to collapse as soon as they form.
However, in glasses that require the generation of a moderate amount of bubbles, such as champagne glasses, the surface is intentionally made uneven to protect the bubbles from the crushing force caused by surface tension and make it easier for bubbles to form. The same thing happens when you put small objects like raisins or peanuts in carbonated water. The wrinkled surface of a raisin makes it easy for bubbles to form in the carbonated water, and when enough bubbles accumulate, they float the raisin to the surface of the liquid like a lifebuoy. When the bubbles reach the surface, they pop, and the raisin sinks again. This process is repeated until the gas in the carbonated water is gone, which is why the raisins bounce up and down in the water.
In their study, Spagnoli and his colleagues developed a mathematical model to predict how many times an object, such as a raisin, would move up and down in carbonated water. The model incorporated the bubble growth rate, the object's shape, size, and surface roughness, as well as the rate at which the liquid loses carbonation based on the shape of the container, and the currents created by the bubble activity. The study found that the surface area-to-volume ratio of the object had a significant effect on the number of movements, while the resistance of the liquid against the object was relatively unimportant.
'The mathematical model using carbonated water and raisins provides a way to determine quantities that are difficult to measure using quantities that are easier to measure. For example, by simply observing the vibration frequency of an object, we can learn a lot about the surface of the object at a microscopic level without looking at the details directly,' said Spagnoli. In addition to carbonated water, magma containing dissolved gas is a typical example of a supersaturated liquid, and if small objects moving within magma affect volcanic eruptions, this could be useful for analyzing them.
In addition, the dancing raisins study offers insights into the active substances in liquids, such as microorganisms swimming in water and the interiors of cells filled with liquid. 'From geophysics to biology, new insights into the physical world will continue to emerge from tabletop experiments, and perhaps even in the kitchen,' says Spagnoli.
Related Posts:
