In a new experiment, researchers to produce an extremely loud noise in fact, the team says it was right at the limit of being the loudest possible sound that could ever be produced in water.
A team from SLAC National Accelerator Laboratory used X-ray laser to generate extremely loud underwater sound by blasting tiny jets of water, creating sound pressures above 270 decibels.
Sound is measured on decibel scale, at the lowest end of which is the limit of human hearing. In comparison, sound of normal conversations is at 55 decibels, a chain saw at 100 decibels, jet taking off 330ft away is at 130 decibels, and the sound of a rock concert is 150 decibels.
However, in air, a sound can’t get higher than around 194 decibels, but in water it’s about 270. For creating the sound, the researchers blasted micro-jets of water thinner than a hair strand,
With Linac Coherent Light Source (LCLS), an insanely powerful X-ray laser that can do things like heating water to 100,000°C in less than a millionth of a millionth of a second.
When the short X-ray pulses hit the water it vaporized, it generated a shockwave. The shockwave then traveled through the jet and formed copies of itself in a ‘shockwave train’ made up of alternating high and low pressure zones.
Once the sound intensity went above a certain threshold, the water broke down and turned into small vapor-filled bubbles, which immediately collapsed in a process known as cavitation.
Also, since the pressure in the X-ray-generated sound wave is just below the break-apart threshold, it is as loud as an underwater sound can be.
The team believes that by better understanding how these shockwave trains work, it may be possible to find ways to protect miniature samples undergoing atomic-scale analysis inside water jets from damage, which would be of great help in the development of better drugs and materials.