The document discusses the convection cycle and how it relates to weather changes. It mentions that when molecules are heated or cooled, their substance and properties change, and different types of air masses including warm or cold and moist or dry can interact to cause weather changes as one air mass replaces another.

1. Why weather happens. Rain or Shine?

2. THE CONVECTION CYCLE! What happens when molecules are heated? What about when they cool? How do the substance and molecular properties change?

3. cold air mass meeting a warm air mass Air Masses warm, moist warm, dry cold, moist cold, dry

4. Why does the weather change? Cold air mass -> Warm air mass Warm air mass -> Cold air mass