1. DO Now 1._____the measure of the force per unit area of air molecules in the atmosphere at a given altitude (atmospheric pressure) 2._____ most abundant gas in the atmosphere (atmosphere) 3._____layer of the atmosphere weather occurs in (atmospheric layers) 4._____ process by which most thermsl energy in the atmosphere moves (atmospheric heating) 5._____ fast moving wind in the stratosphere (atmospheric layers)

2. Water Cycle 1. What is the water cycle? 2. What is another name for the water cycle? 3. What are the four process of the water cycle? 4. What is evaporation? 5. What is transpiration? 6. What is condensation? 7. What is precipitation?

3. 4.2 The Water Cycle 1. Water cycle- a set of processes powered by the sun that keep our water continuously recycled and naturally filtered. 2. The water cycle is sometimes called the hydrologic cycle. The Sun, wind, weather, and gravity drive the water cycle.

4. 4.2 Water cycle processes 3. The four main processes of the water cycle are evaporation, transpiration, condensation, and precipitation. 4. Evaporation occurs when liquid water has enough energy to leave the liquid phase and become a gas called water vapor.

5. 4.2 Water cycle processes 5. Transpiration is the process in which plants lose oxygen and water through tiny pores on their leaves.

6. 4.2 The Water Cycle 6. Condensation occurs when a gas cools and form droplets of liquid.(forms clouds)

7. 4.2 Water cycle processes 7. Precipitation is any form of condensed water vapor in the atmosphere falling back to Earth. This includes rain, snow, sleet, and hail.