- Computer with Internet access
- Wall or blank Xpeditions outline map of the world showing latitude and longitude lines
- Globe (optional)
- Paper and writing utensils
- identify various bodies of water on the planet, discuss their observations about the amount of water on the planet, and hypothesize about the potential wave size in each location;
- learn the different parts of the wave and identify them;
- look at the effects of wave height, wavelength, and wave period on the overall size of a wave; and
- create various scenarios on the online National Geographic Wave Simulator, and discuss additional forces that might affect the way a boat might react to varying wave sizes.
Acquiring Geographic Information
Answering Geographic Questions
Analyzing Geographic Information
S u g g e s t e d P r o c e d u r e
Some of the largest recorded waves exist in what is often referred to as the Southern Ocean, the stretch of water surrounding Antarctica to the 60: south latitude. In these southern latitudes, the winds and currents wrap around the planet with little land to slow them down. Sailors refer to them as the "Roaring 40s," "Furious 50s," and "Screaming 60s" for the latitudes where these winds occur. Look at the Drake Channel between the tip of South America and the Antarctic peninsula, where some of the largest waves in the world occur. Why do the students think this phenomenon occurs?
Send the students in pairs to the National Geographic Wave Simulator and ask them to experiment with the various controls. After a few minutes, have them record all of their observations. What did they notice about the position of the boat as the waves rolled past? Explain to them that in the real world, the wind acts as a key force on a boat.
When a boat encounters high waves and strong winds, it is virtually impossible to sail against the wind and over the waves so the boats actually surf down the waves. However, if the wind carries the boat faster than the waves, then the boat risks plowing into the wave ahead of it and pitch-poling (when the stern flips over the bow and the boat cartwheels). To prevent this from happening, sailors have two options: they can take down their sailsa technique called "reefing"or they can throw out what is called a sea anchor or "drogue." A sea anchor creates drag to slow down the boat, much like a drag racing car uses a parachute off the back to slow down after a race.
Send the students back to the simulator and assign each group a different geographical scenario (i.e. you are sailing through the Drake channel, what would the wave and wind conditions resemble and what should you do to best handle them?). Have them determine which variables they may want to increase/decrease to improve the situation. Students can explore the National Geographic Sailing Simulator to learn more nautical terms and see how boats behave in the wind.
Using the simulator, try to re-create the waves from this storm as compared to other ones discovered during the lesson. What did the students observe about these wave sets? Which element played the greatest role during the storm: wave height, wavelength, wave period, or wind? Why?