Chap 16, Sect 1 (Water in the Air) Take out 2 sheets of closed notes from your blue tubs. Glue both sheets in and copy your objectives. Objectives: Explain how water moves through the water cycle (this is review and is important because this is what can build or give power to storms). Understand the role of humidity in the air. Describe 3 types of clouds.

Understanding Weather: Open books to p. 482 Tech Terms: Weather: the condition of the atmosphere at a certain time and place. Weather is affected by the amount of water vapor in the air.

Weather vs. Climate The main difference between weather and climate is the length of time over which both are measured. Weather conditions vary from day to day and include temperature, humidity, precipitation, wind, and visibility.  2) Climate: the average weather condition in an area over a long period of time. Climate is mostly determined by two factors—temperature and precipitation.

3. humidity – the amount of water vapor in the air. This graph shows that as air gets warmer, the amount of water vapor that the air can hold increases

4. relative humidity – the amount of water vapor in the air compared to the max amount the air can hold at a given temperature. Suppose that 1 m3 of air at a certain temperature can hold 24 g of water vapor. However, you know that the air actually contains 18 g of water vapor. What is the relative humidity? You can calculate the relative humidity by using the following formula:

Condensation/Saturation Point Remember seeing water droplets form on the outside of a glass of ice water. Where did those water drops come from? The water came from the surrounding air, and droplets formed as a result of Condensation. Before condensation can occur, the air must be saturated, which means that the air must have a relative humidity of 100%. Condensation occurs when saturated air cools.

(High energy air = High relative humidity) This builds storms! WHAT DOES IT HAVE TO DO WITH HOW WEATHER AND CLIMATE ARE PRODUCED ON EARTH? When air has MORE energy, MORE water vapor can fit within the gas particles (High energy air = High relative humidity) High energy air is LOW pressure This builds storms!

(Low energy air = Low relative humidity) When air has LESS energy, LESS water vapor can fit within the gas particles (Low energy air = Low relative humidity) Low energy air is HIGH pressure – “HIGH AND DRY”

Let’s Review: 5. condensation – the process of a gas becoming a liquid (air must have a relative humidity of 100% and air must become cool for this to happen). What is a cloud? 6. precipitation - water, in solid or liquid form, that falls from the air to Earth. (rain, snow, sleet, and hail)

3 Types of Precipitation: What are the differences? Rain Sleet/Snow Hail What are the differences?

Rain: water drop/nucleus in a cloud begins smaller than this period Rain: water drop/nucleus in a cloud begins smaller than this period. It must grow 100x the size before it drops as rain! Sleet: freezing air, creates falling ice Snow: water vapor changes to a solid high in atmosphere Hail: updrafts of warm and cold air refreezing new layers.

Why do clouds float?

7. Cumulus clouds – clouds that look like puffy balls of cotton and usually indicate fair weather – until they turn into cumulonimbus. Draw Me

8. Stratus clouds – clouds that form in flat layers and may produce drizzle, rain, or snow. Draw Me

9. Cirrus clouds – clouds that are thin and feathery, found at high altitudes, and as they get thicker, indicate a change in weather. Draw Me

Draw the layers of clouds in the atmosphere in your IAN!

Windward/Leeward Weather -The mountain forces air to rise. It cools, condenses and rains. When it gets to the other side (leeward) the moisture is gone. It sinks and is dry. -Most deserts form on this side of a coastal mountain chain. -Ex: Andes Mtns/ Atacambe Desert

Section Summary Humidity describes the amount of water vapor in the air. Relative humidity is a way to express humidity. When the temperature of the air cools to its dew point, the air has reached saturation and condensation occurs. Clouds form as air cools to its dew point. Clouds are classified by form and by the altitude at which they form. Precipitation occurs when the water vapor that condenses in the atmosphere is more dense and falls back to Earth in solid or liquid form

Exit Pass

Brainpop Clouds Brainpop Atmosphere In Summary: Review brainpops as a class and complete the class quiz as a group. Brainpop Clouds Brainpop Atmosphere