Physics surprised us again, after a group of researchers discovered that simple liquids can have breaking points beyond which they suddenly fracture – just like solids.
A new study, in Physical Review Lettersrevealed that, in addition to stretching and flowing, liquids can also crackle.
From 3D printing technology to biological systems inside our bodies, this discovery, made by researchers at Drexel University in the USA and ExxonMobil, comes to shake fluid mechanics.
It all started when scientists were experimenting to see how viscous liquids respond to intense forces. Initially thought the laboratory equipment had broken down.
“The fracture caused a very loud popping noise that actually scared me,” the chemical engineer told . Thamires Limafrom Drexel University.
“What we observed was so unexpected. Once we confirmed the phenomenon, the research became a completely different scientific endeavor”, said, in turn, Nicolas Alvarezchemical engineer at Drexel University.
The same magazine knows that the team repeated the experiments a few times to ensure the results were reliable. The assembly involved liquids placed between two metal plates, observed by a high-speed camera, and with a variety of forces applied.
O first snap occurred when the liquid was pulled with a force comparable to that of a bag of bricks suspended in an area the size of a fingernail.
This was in a liquid of tar-like mixture of hydrocarbonsand the same breaking point was later found in a different liquid, a styrene oligomer – which was also thick and tar-like.
Stress builds up differently in a thicker, more viscous liquid compared to a looser, less viscous one.
Based on these experiences, Thicker liquids may crack even when drawn more slowly – but the amount of force required appears to be the same regardless of the viscosity involved.
While it was previously known that liquids could crack if cooled enough or mixed to achieve the right properties, this is a new discovery.
“We have shown that, if separated with sufficient force by area, a simple liquid – a flowing liquid – will reach what we call a tipping point. Voltage Reviewin which it will actually fracture like a solid”, says Lima.
“And this is probably true for all simple liquidsincluding common examples such as water and oil“, he added.
