Weather, Climate, and Me Lesson 6 What make the wind?

WHAT MAKES THE WIND? Think about …. WHY DO AIR MASSES MOVE? What did we learn from the last lesson about the relationship between temperature and wind direction? What evidence do we have about the movement of weather from West to East? WHAT CAUSES WIND? WHY DO AIR MASSES MOVE? WHAT MAKES THE WIND?

Weather, Climate, and ME Lesson 6 What makes the wind? What are the patterns of the prevailing winds?

What we think about …… …the sun’s heating of the Earth, air temperature, and how winds occur. Consider the following: 1. Air pressure and temperature 2. Air pressure changes at elevation 3. Air pressure expansion at elevation Record your ideas.

Also consider that….. ….air pressure decreases with an increase in elevation. ….air pressure is determined by the weight of the air above. ….air pressure expands as the pressure lowers and, as a result, the temperature decreases. (Recall the pop bottle experiment.)

Movement of air masses requires energy. Where do you think this energy comes from? How is this related to how winds occur?

Balloon Lab (pages 20 and 21) Procedure: 1. Partially inflate the balloon and put it over the opening of the flask. 2. Measure the circumference of the balloon. 3. Put the flask in warm water for ____ minutes, remove and measure the circumference of the balloon. 4. Put the flask in cold water for ____ minutes, remove and measure the circumference of the balloon. 5. Return the flask to room temperature and measure the circumference of the balloon. 6. Make a data chart. What trends did you see? 7. Draw and label……..

How does temperature affect the expansion of air? Cool video #1 Cool video #2 Cool video #3

Share your ideas…. Did you include…. 1. why you think warm air expands and cold air contracts? 2. a discussion of air movement in the flask and balloon? 3. how this activity relates to air movement in the atmosphere?

Discuss the following terms. Convection Molecules Density Expand Contract Air How are these terms related in explaining the results of your investigation?

Ask yourself the following…. Did we observe convection in this investigation? Did we see/record evidence of… 1. …the movement of air due to expansion and contraction? 2. …pressure caused by change of temperature? 3. …movement of air (rising warm air/sinking cold air) due to density? How could we set up a demonstration that shows the movement of air due to convection?

CONVECTION DEMONSTRATION

CONVECTION VIDEOS Cool Convection Video #1 Cool Convection Video #2

What Makes the Wind? Read pages 22 and 23 in your journal. Highlight key terms and ideas

Surface Pressure Change Map Learning Lesson: Drawing Conclusions - Surface Pressure Change Map Surface Pressure Change Map 1. Lightly draw blue lines connecting equal values of the +2 millibars pressure change.

Learning Lesson: Drawing Conclusions - Surface Pressure Change Map Solutions

Learning Lesson: Drawing Conclusions - Surface Pressure Change Map Solutions …..continued 2. Using a blue pencil, draw the remaining “positive” pressure change value(s) at two millibars intervals.

Solution 2 Solution 2

…..continued 3. Using red pencils draw a line connecting equal pressure values of less than 0. 4. Finally, using black, draw a line the zero line.

Solutions 3 and 4 Solution 3

…..continued Cold fronts are often located I areas where pressure change is the greatest. The front represents the boundary of different air masses. Cold air is more dense than warm air so when a cold front passes your location, the pressure increases. We analyze for pressure change to look for these boundaries. We can also tell where high pressure and low pressure systems are moving by looking where the greatest change is occurring. 5. Shade, in red, the region where the surface pressure change is -2 mb or less. 6. Shade, in blue, the region where the surface pressure change is +2 mb o rmore.

Solution 4 Answers 5 and 6

…and this is what it looks like on a actual weather map.

Wrap Up Discussion Discuss: 1. How the sun’s warming of the land and oceans changes the temperature of the air. 2. Warmer, less dense, air masses rise pushed up by the cooler denser air moving in. 3. Cooler air has molecules that are moving more slowly and are closer together, making the air denser.

Review you weather data chart. How does wind relate to an increase or decrease in temperature? What is the evidence to support your conclusion? What evidence do you have of warm air being forced up by colder air moving underneath. It is this air movement that creates the wind. Complete you journal entry.

Weather, Climate, and ME Lesson 7 What happens when warm and cold air masses meet? How are clouds formed?

REVIEW What have you learned about what makes the wind? 1. Warm air __________resulting in convection. 2. Describe the density of warm air compared to cold air. 3. Describe the molecules of warm air compared to cold air. 4. Describe mass of warm air compared to cold air.

They are large bodies of air about the same temperature. ….continued What are air masses? They are large bodies of air about the same temperature. What do you think will happen if/when a warm air mass and a cold air mass come together?

LET’S FIND OUT!

CONVECTION CURRENTS Mixing Cold and Hot Water View this… Cool Convection Video Journal Entry pages 25 and 26 Draw and label what you think will happen when you remove the divider is removed between the how and cold water. Explain why you think that will happen. Draw and label what happened. Explain your results. Use the terms convection and density in your response.

Discuss: ….your observations. ….what you think is happening to the warm and cold water. ….the patterns you observe. ….your explanation of why this is happening. how this demonstrates what is happening between warm and cold air masses in the atmosphere.

Now What do you think about… …what happens when warm and cold air masses meet?