An ultrafine bubble (also called nano bubbles) is the size of less than 1 micrometer. They are invisible to the naked eye. They are visible with the aid of laser light scattering. If you line up 10,000 nano bubbles, it will still be short of one millimeter. Nano is equal to the fraction 1/1 billion. Nano bubbles have many potential applications in many different fields. This technology can put oxygen or ozone gas into water as tiny nano sized bubbles. And the study in each area is being done.