Bubbles usually come in 2 forms which are:

1. Bubbles in air. Which consist of transparent film of light viscose substance (liquid), usually spherical (round) enclosing an accumulation of gas i.e. Soap Bubble which float in the outside air. The outside air is not surrounded by liquid but something we call an atmosphere, which in turn is surrounded by a nothingness called a vacuum.
   
2. Bubbles not in air. Which consist of small globules of gas trapped inside a liquid or solid i.e. inside a fizzy drink or hardened glass.
   
   Of course if a gas in liquid is lighter or less dense than the liquid it is in, then it isn't really trapped and will eventually float to the surface and become a none bubble.
   

Bubble related questions (sort of)

1. 
   If the only thing outside our atmosphere is a vacuum then why doesn't it suck all the air out through the hole in the ozone layer?
   
2. 
   Could all the planets with breathable atmosphere be classed as bubbles in the vacuum of space?
   
3. 
   Why, if the Earth is so much heavier than the air that surrounds it, doesn't it drop to the bottom of the atmosphere?