Here's a breakdown:

* Air Masses: Large bodies of air with relatively uniform temperature and humidity.

* Front: The boundary between two different air masses.

There are different types of fronts, each with its own characteristics and weather patterns:

* Cold Front: A cold air mass pushes into a warmer air mass, bringing strong winds, thunderstorms, and sometimes tornadoes.

* Warm Front: A warm air mass pushes into a cooler air mass, bringing gentle rain and fog.

* Stationary Front: Two air masses meet but neither advances, resulting in prolonged periods of rain or drizzle.

* Occluded Front: A cold front overtakes a warm front, forcing the warm air aloft, causing complex and often heavy precipitation.

So, the collision of air masses creates a front, which acts as a boundary zone where weather changes occur.