Shrimps and Sonoluminescence

SAlys Dunn

So, what links sonoluminescence and shrimp? Mantis shrimp have an incredibly strong claw. This claw can move at around 100km per hour! When this claw closes in water it produces a bubble. This is a very special bubble though; it’s called a cavitation bubble. Mantis shrimp can use these cavitation bubbles as a defence mechanism or to stun their prey. Here’s a video of a shrimp making some bubbles: (https://www.youtube.com/watch?v=QXK2G2AzMTU).

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Image Credit: Wikimedia Commons

Whenever the pressure in a liquid suddenly drops, cavitation occurs. This physics phenomena can even break beer bottles. Cavitation bubbles are formed when the force from the shrimp’s claw causes a low pressure bubble of air to be formed within the water. The water around the bubble is at a higher pressure. This difference of pressures causes the bubble to collapse.  This is when all the interesting stuff happens.

The inside of the bubble becomes incredibly hot, estimates are that the temperature of the bubble can reach five to ten thousand Kelvin. This can be hotter than the surface of the sun. Blueish light has also been detected for mere trillionths of a second. The light and heat produced by the bubble is called sonoluminescence. Bubble dynamics and their stability are theorised to be responsible, but sadly scientists have not yet definitively proven how this sonoluminescence occurs.

What if we could harness the heat produced in this very small bubble and scale it up to cause thermonuclear fusion? Nuclear fusion, the joining of two atomic nuclei into one which releases heat, requires a lot of heat energy to get started and as of yet is incredibly unstable. Could we solve the global challenge of finding a source of energy that is both carbon-neutral and sustainable, with a single bubble?