Effervescent describes something that fizzes and bubbles, like soda when you first open it or an antacid tablet dropped into water. The bubbles form because gases are escaping from the liquid, creating that lively, fizzing action you can see and hear.

When scientists talk about an effervescent reaction, they mean one that produces gas bubbles, like mixing baking soda and vinegar in a homemade volcano experiment.

People also use effervescent to describe someone with a bubbly, lively personality. An effervescent person brings energy and enthusiasm into a room, making others smile and feel more energized themselves. They might laugh easily, get excited about ideas, and generally seem to sparkle with life. Just as bubbles in soda rise and pop with energy, an effervescent personality lifts the mood of everyone around them.

The noun form is effervescence, which describes both the physical bubbling and that quality of bubbly liveliness: “Her effervescence made even boring tasks feel fun.”