Exhibit blog

Talking about sounds tha we cannot hear always makes me think of dolphins…

Not only they are beautiful mammals, they can swim much faster than any Olympic champion and they can hear much more than we do, but someone says that they can play with beautiful bubble rings!

Douglas Adams was right! They must come from another world…

If you want to hear more about dolphins and bubble rings, here is one of my favourite links.

Further reading

  • Harfield CJ, Ovenden N, Memoli G, Jones PH and Stride EPJ. 2012 Theoretical characterisation of the radial and translational motion of coated microbubbles under acoustic excitation. In preparation
  • Jones PH, Stride E, Saffari N. 2006 Trapping and manipulation of microscopic bubbles with a scanning optical tweezer, Applied Physics Letters 89, 081113
  • Memoli G, Pawlikowska A, Harfield C, Jones PH, Stride E, Gelat P, Hodnett M, Zeqiri B. 2012 Simultaneous acoustical and optical trapping of microbubbles. In preparation.

Bubbles are everywhere – think of champagne, boiling water, inkjet printers, cleaning fluids and volcanoes. Interestingly, there is a special connection between gas bubbles and sound waves. Sound can be used to create bubbles, as happens in treatment for kidney stones, and bubbles can also alter sounds, as happens when waves crash onto the beach.

When bubbles are probed by sound, they 'ring' differently according to their properties and surroundings. As a result, they can be used as cost-effective medical sensors, for example for detecting cancer in the human body.

Acoustic bubble research could lead to less intrusive, cheaper, more accurate medical diagnosis and treatment. It could also lead to food which tastes better and new ways to characterise industrial processes.

How it works

When you hit a glass of wine with your finger, a sound is produced. The pitch of the sound depends - among the other things - on how much liquid the glass contains, the shape of the glass and the temperature of the room.

Similarly, a bubble is essentially an empty sphere filled with air. When it is pinged with a sound wave, it responds at particular frequencies which reveal the properties of the surrounding environment.

This exhibit demonstrates the potential shown by bubbles and microbubbles in medicine, where the effect can be used with ultrasound to improve cancer diagnosis from 60% to 95%.

It also demonstrates the use of the technique in industrial applications, where bubbles can act as precise sensors. By trapping them in cages of light and sound, called "sono-optical tweezers", the sound emissions can be studied in controlled conditions, just like tuning a guitar with a fork.


This video shows Dr Gianluca Memoli talking about controlling bubbles in a can of coke with a spoon.

This video shows Chris Fury building a bubble-powered mini-space shuttle, using simple materials.

This video shows Dr Gianluca Memoli explaining the sound of bubbles.

This video shows scientists from this exhibit talking about life as a scientist.