Lets talk about a very interesting phenomenon the reason for which is still unknown .
Sonoluminescence is the emission of light by bubbles in a liquid when
excited by sound . It was discovered in 1934 .
SImple enough : Make a small bubble in a liquid . throw some sound on it
and it emits light . Wow !
It is an unstable phenomeneon and lasts for a very short time .
It is still a mystery in the Physics world because nobody
understands how a low-energy-density sound wave can concentrate
such a lot of energy in such a small volume to create light .
ANd the emitted light has a very short wavelength ( ultraviolet) .
This means that it has very high energy . The observed spectrum of
light indicated that the bubble is atleast 10,000 degrees Celsius .
Physicists think that they can use this huge energy to cause fusion
if the bubble is hot enough and the pressure is high enough then
thermonuclear fusion( a reaction that causes Sun to burn ) may be
a possibility .
More interesting facts about Sonoluminescence :
1. light flashes from the bubble last for very short times < 12 picoseconds.
2. The bubble has to be really small ~ 1 micrometer in diameter .
3. Single bubble sonoluminescence tends to be stable .
4. Addition of small amounts to nobel gas to the bubble increases the
intensity of emitted light drastically .