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Phenomenon
Phenomenon
Global high level winds blow east to west at the poles and west to east at mid-latitudes. At the equator winds blow from east to west. Why?
Earth's rotation has affects the movement of air masses and storms.
- Vie w the video.
- Observe wind currents using EARTH. Describe patterns that you observe. To view winds at different altitudes, click on EARTH, and change the height. hPa stands for hectapascals and it is a measure of pressure.
- Explain why prevailing winds curve and move in expected directions.
- Explain the Coriolis effect.
Make a Model
- Mark the equator, latitudes 30º N and S, and latitudes 60º N and S on your sphere.
- Holding the sphere at the poles, slowly rotate the sphere.
- As you rotate the sphere, have a partner try to draw a straight line from 30º N southward to the equator. Then try to draw a straight line from 30º N northward toward the 60ºN. Complete the wind belts by trying to draw a straight line from the north pole to 60º N latitude.
Materials
- Spherical object - ball, balloon, or globe
- Washable marker
- Pencil and tape to make a handle for rotation. A suction cup with a dowel works well also.
Big Ideas
Big Ideas
- Wind is caused by differences in air pressure.
- Wind is a horizontal flow of air from higher pressure to lower pressure.
- Unequal heating of Earth's surface is related to development of convection cells.
Phenomenon
Phenomenon
The troposphere is the layer of the atmosphere where weather occurs. The troposphere at the equator extends upward 16-18 kilometers. The troposphere at the poles extends upward 7-8 kilometers. Why?
View the video, then use the diagram to answer the following questions.
- Hadley cells are located between the intertropical convergence zone and 30ºN and 30ºS latitudes. Explain the pattern of air circulation in Hadley cells.
- Mid-latitude cells are located between 30ºN/S latitudes and 60ºN/S latitudes. Explain the pattern of air circulation in mid-latitude cells.
- Polar cells are located between 60ºN/S and 90ºN/S. Explain the pattern of air circulation in polar cells.
Image credit: National Geographic
Make a Model
- Place a thermometer in the bottle.
- Cap the soda bottle with a balloon.
- Record the temperature.
- Position the lamp at the base of the soda bottle.
- Observe what happens when the lamp is turn on. Record your observations.
- Place the soda bottle on a bed of ice. Observe what happens. Record your observations.
Explain your observations.
Materials
- balloon
- 1-liter soda bottle
- thermometer
- lamp for heat
- Ice bath
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