This week's theme: Bubbles

bub·ble noun, often attributive \ˈbə-bəl\

1. a small globule typically hollow and light: as
   1. a small body of gas within a liquid
   2. a thin film of liquid inflated with air or gas
   3. a globule in a transparent solid
   4. something (as a plastic or inflatable structure) that is hemispherical or semicylindrical