Read each slide, some slides have information to record on your organizer. Some slides have numbers that go with the question or red and underlined to use for answering the questions.
Essential Question: How does unequal heating and the Earth s rotation affect wind & weather patterns? Standards: S6E4a. Demonstrate that land and water absorb and lose heat at different rates and explain the resulting effects on weather patterns. S6E4b. Relate unequal heating of land and water surfaces to form large global wind systems S6E2c. Relate the tilt of the earth to the distribution of sunlight throughout the year and its effect on climate.
Learning Target: When the temperature of a fluid (like air) changes, so does its density. As the density of air changes, it begins to move - cooler, more dense air sinks and warmer, less dense air rises. So differences in the temperature of air in the atmosphere sets air in motion, which drives all of the weather on Earth. To truly understand this, we need to step back and explore why and where on earth there are temperature differences.
Objectives Explain how the sun heats Earth's surface unevenly. Describe global patterns of wind, precipitation, and ocean currents.
Read ONLY! Uneven Heating of Earth's Surface Energy from the sun warms Earth's surface. But because of Earth's spherical shape, different locations on Earth's surface receive different amounts of solar energy. Near the equator, the sun's rays strike the surface most directly. At latitudes farther from the equator the rays strike Earth's surface at lower angles, causing the same amount of solar energy to be spread over a larger area (Figure 34-6). As a result, regions on Earth's surface farther from the equator absorb less heat and generally experience cooler temperatures than regions closer to the equator. These temperature differences also drive global air and water movements.
1. Read then summarize use the red to help you in the summary! The uneven heating of the Earth's surface is caused by the sun. This occurs because the Earth is a tilted sphere and the sun does not heat all its surfaces equally and because the sun's heat penetrates land and water at different rates.
2. This uneven heating of land forms wind systems. (Figure 34-6).
3. Wind is caused by differences in air pressure. Areas of high pressure move to areas of low pressure. Air pressure is related to density. Let s review density.
Which one has greater density? Greater pressure? Greater Density Greater Pressure Lower Density Lower Pressure
We will consider Density and Pressure to be the same. What about temperature? What did you learn about temperature and density?
Look at the images below. Identify which image has: Higher Temperature, Higher Density, Higher Pressure. Higher Temperature Lower Density Lower Pressure Lower Temperature Higher Density Higher Pressure
4.Temperature, Density and Pressure Density increases, Pressure increases Temperature decreases Temperature increases Density decreases, Pressure decreases
Let s apply these concepts back to wind. Wind is caused by differences in air pressure. Areas of high pressure move to areas of low pressure.
In which direction would the wind move below. Higher Temperature Lower Density Lower Pressure Lower Temperature Higher Density Higher Pressure
Why? Higher Temperature Lower Density Lower Pressure Lower Temperature Higher Density Higher Pressure
Think of it this way matter naturally wants to move from where it is crowded to where it is less crowded. This concept is true for all of science. Higher Temperature Lower Density Lower Pressure Lower Temperature Higher Density Higher Pressure
Particles naturally want to move from where they are more crowded to where they are less crowded. 17
5. Which areas of the earth have air that is low pressure (low density)? Why? What about high pressure (high density)?
Distributed Summarizing: Turn to a seat partner and describe how wind moves. Together discuss the following question: What makes wind travel at faster speeds?
8. Differences in density and pressure cause wind and air movement. The movement of air occurs in convection currents. Convection currents are simply the transfer of heat by the circulation or movement of the heated parts of a liquid or gas.
10. Everyday Examples of Convection Currents. http://www.healthyheating.com/definitions/heattransfer-convection.htm#.vd7sifmjoso
12. Large Convection Currents are formed because of the temperature differences between the equator and the poles. This produces global wind systems.
The sinking of cold, dense air and the rising of warm, less dense air do not explain everything about wind. What other factor have we discussed previously that affects the direction of winds on the earth s surface?
Surface winds and surface currents are affected by the rotation of the Earth (the Coriolis Effect) Because Earth rotates toward the east, winds appear to curve to the right in the northern hemisphere and to the left in the southern hemisphere
The effect of the earth s rotation (Coriolis Effect) on Winds http://www.classzone.com/books/earth_science/terc/content/visualizations/es1904/e s1904page01.cfm?chapter_no=visualization http://www.classzone.com/books/earth_science/terc/content/visualizations/es1905 /es1905page01.cfm?chapter_no=visualization
The flow of air caused by unequal heating of the Earth s surface and the rotation of the Earth (Coriolis Effect) creates distinct wind patterns on Earth s surface. These wind systems not only influence the weather, they also determine when and where ships and planes travel most efficiently.
Below is a diagram showing the global wind patterns that distribute heat and moisture around the globe. Use with question 15
What are the global wind patterns? The equator receives the Sun's direct rays. Here, air is heated and rises, leaving low pressure areas behind. Moving to about thirty degrees north and south of the equator, the warm air from the equator begins to cool and sink. Between thirty degrees latitude and the equator, most of the cooling sinking air moves back to the equator. The rest of the air flows toward the poles.
Distributed Summarizing: Turn to a seat partner and describe the factors that influence global wind patterns.
Global wind systems determine the major weather patterns for the entire planet. Smaller wind systems affect local weather. Two such wind systems are sea breezes and land breezes.
85 F Low Pressure 65 F High Pressure Look at the temperatures of the land and the sea in this diagram. Which direction would the wind blow? Why?
85 F Low Pressure 65 F High Pressure A sea breeze occurs when wind is moving from the sea towards land.
Land heats up and cools down faster than water. How does this affect wind?
55 F High Pressure 65 F Low Pressure At night when the earth s surface is no longer being heated by the sun, the land cools much more rapidly than ocean water. What happens to the wind?
55 F High Pressure 65 F Low Pressure A land breeze occurs when wind is moving from the land to the sea.
How do sea breezes and land breezes affect local weather? http://www.nc-climate.ncsu.edu/edu/k12/.breezes
Local winds: Sea Breeze and Land Breeze
What is a High Pressure System? A high pressure system is a whirling mass of cool, dry air that generally brings fair weather and light winds. When viewed from above, winds spiral out of a highpressure center in a clockwise rotation in the Northern Hemisphere. These bring sunny skies. A high pressure system is represented as a big, blue H. H
What is a Low Pressure System? A low pressure system is a whirling mass of warm, moist air that generally brings stormy weather with strong winds. When viewed from above, winds spiral into a low-pressure center in a counterclockwise rotation in the Northern Hemisphere. A low pressure system is represented as a big, red L. L
Sea Breeze Land Breeze
Identify which diagram illustrates a Sea Breeze and a Land Breeze. Explain why. Include high and low air pressure in your explanation.
High Pressure Sea Breeze Low Pressure Sea breeze, a local wind system characterized by a flow from sea to land during the day. Sea breezes alternate with land breezes along the coastal regions of oceans or large lakes in the absence of a strong largescale wind system during periods of strong daytime heating A land breeze is a local nighttime and early morning wind that occurs along coasts and blows offshore (from the land out to sea). It arises at sunset, when the sea surface is warmer than the adjacent land due to the land cooling off faster and having a lower heat capacity, and continues into the early morning hours until the heating of the day begins. Although commonly associated with ocean shorelines, land breezes can also be experienced near lakes and other large bodies of water. Low Pressure Land Breeze High Pressure
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