Air pressure differences cause air convection currents that lead to precipitation formation. Warm, moist air rises at the equator in low pressure areas, cools and condenses into rain. The air then falls in high pressure areas, where it is dry and dense. This circulation pattern explains how moisture is evaporated from oceans and condenses into rain through rising and cooling air convection currents.

1. Resource 8a Precipitation Formation Sun Rain Air Pressure

2. Air pressure: Highs and Lows Dry air Cold Dense Heavy Falls High Pressure System: Moist air Warm Sparse Light Rises Low Pressure System:

3. Air is heated and it rises at the equator causing a low pressure area. Air pressure: Highs and Lows Low Pressure Earth’s Surface Equator

4. Air pressure: Highs and Lows High Pressure As the air rises, it cools and falls back to the earth’s surface creating a high pressure area. High Pressure Low Pressure Earth’s Surface Equator These are called air convection currents

5. Moisture is evaporated from the ocean Moisture rises in the air convection current The air cools as it rises Moisture condenses into rain So how is preciptiation formed?

6. Remember we are explaining the process of precipitation formation… http://www.kgs.ku.edu/Publications/PIC/pic23.html