|Cowabunga! Some Cool Wave Theories
Prep for Teachers
Prior to the activity, bookmark each of the Web sites used in the lesson, or use the "Condition Black
" Portaportal account by logging onto www.portaportal.com and logging in as a guest: ConditionBlack (no spaces). When logged in as a guest, you (and/or your students) cannot make changes to the Portaportal account. If you create your own account, you will be able to add or delete sites whenever you like.
| Load the Shockwave and Flash plug-ins onto all computers in your classroom, available free at www.macromedia.com (see Media Component section above for links). CUE the videotape to its appropriate starting point based on visual and audio cues and become familiar with all starts and stops. Prepare copies of the handouts.
Prepare the student organizers and handouts for each part of the lesson by copying them for each student. Make sure students have generic note taking materials as needed.
Be sure that video camera is fully charged and have a rewound, blank DV tape loaded. If the camera is to remain stationary, it is advisable to use a power adaptor when filming. Be sure to have the necessary video editing software loaded and camera-to-computer (firewire) cables available for downloading video clips.
When using media, always provide your students with a FOCUS FOR MEDIA INTERACTION-a specific task to complete and/or information to identify during or after viewing of video segments, Web sites, or other multimedia elements.
CUE Nature: "Condition Black" to the opening of the episode as the first video image appears.
Poll your students: Who likes going to the beach? What beaches do you go to? What do you like to do at the beach? Hopefully some kids will say body surf, boogie board or surf. If nobody says "surf," ask your students if they have ever seen people surfing. Tell your students they are about to see a clip of some of the best surfers in the world surfing some of the largest waves in recorded history. Before you play the cued video, provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to think about what might be the main cause of the waves the surfers are riding. Ask the students to write down their answers on their "WaveFocus" organizer. PLAY the video. PAUSE the video approximately 5 seconds after you hear the narrator say "…craving for adventure" and you can see the image of the surfer moving from right to left at the bottom of the huge wave just as it begins to break. Ask students again, "What do you think is the main cause of the huge waves?" Here the answers will vary. Some may say a storm-good answer. A storm did have something to do with these waves but it wasn't the main reason. Also point out that on the day of the huge waves it was sunny. Some may say an underwater earthquake. It's another excellent guess-but no. Underwater volcano? Nope. Tsunami? Nope. (here you should refer to the WaveLingo work sheet to discuss what Tsunamis are). Tidal wave? No, and again you can refer to the WaveLingo work sheet to discuss Tsunamis and Tidal Waves. The most important factor that created some of the largest waves in recorded history was wind. This lesson will explain the role wind plays in creating ocean waves.
With the still image from the Introductory Activity paused on screen, ask the students how big they think the wave is. Ask the students how they made their guesses. Did anyone use a method to make their guess? What method did you use? Ask a student to come up to the TV with the image paused and roughly figure out how big the surfer is (6 ft tall, but hunched over, so maybe 5 ft). Have the student use a dry erase marker to roughly mark off how many surfers would fit within the wave. (If you want to be more exact, measure the height of the image of the surfer with a ruler and use that estimate to measure the height of the wave.) Make a note of the class estimate on the board. NOTE:
when using a dry-erase marker on your TV screen make sure it is a dry-erase marker and make sure your monitor has a glass screen (plastic screens do not work).
Explain to the class that the waves we just watched are called ocean waves or surf that originate hundred or even thousands of miles away as swells caused by storms and wind. When you go to the beaches in the NYC area, you usually see waves that are between 2-6 feet tall. Ask the class why they think Hawaii has such great surfing waves (Answers will vary). Other than waves associated with big storms, earthquakes, tsunamis, etc. do you think ocean waves can ever be dangerous? FAST FORWARD the video to just before the point where the narrator says, "In January 1998 the National Weather Service…" and the visual image changes from a wave hitting the rocks to a crowded beach. Provide your students with a FOCUS FOR MEDIA INTERACTION-asking them to answer question 2 on their WaveFocus Organizer: What is Condition Black
and who decides to declare it? PLAY the video until you hear the announcer say, "…a source of excitement and anticipation." Visual cue is a lone surfer on the rocks. Repeat question 2 and field answers. (Correct answers are: Condition Black is when wave heights are predicted to be over 25-feet and people are not allowed near the water, and the National Civil Defense Department orders a Condition Black.) If students seem lost or answered the questions incorrectly, rewind the tape & play it again.
(NOTE: This video is available as a streaming video on the Nature Web site at http://www.pbs.org/wnet/nature/database.html. See the "Media Components: Video" section of this lesson for more details.)
FAST FORWARD the tape to a scene of waves crashing and you hear a radio report of local maritime conditions. NOTE: when fast-forwarding through large segments of video, hit stop first-the fast-forward will go faster. Provide your students with a FOCUS FOR MEDIA INTERACTION-asking them to answer questions 3-4 on their WaveFocus Organizer: What are the three factors that affect ocean waves? How does the ocean floor affect the wave? PLAY the video for approximately 2 minutes until you hear the scientist say, "…that's where you want to be, in the curl." Then wait about 5 seconds and PAUSE the tape on the image of the surfer in the curl. Repeat questions 3-4 and field answers. (Correct answers: 3) a) the wind speed, b) the fetch or distance over which the wind is blowing, and c) the duration the wind is blowing over the area. 4) A gradual sloping ocean bottom will produce waves that spill and crumble, while an ocean bottom with an abrupt shelf will create plunging top-to-bottom breaking curls.) If students seem lost or answered the questions incorrectly, rewind the tape & play it again.
Provide your students with a FOCUS FOR MEDIA INTERACTION-asking them to answer questions 5-6 on their WaveFocus Organizer: How do the oceanographers predict swells? How do the surfers use the scientific information? PLAY the video from the previous pause point. PAUSE at the point where the oceanographer says, "…in between the crests and troughs" and the video image is a cross section of a wave with a buoy on it. Go over the new vocabulary words found on WaveLingo Organizer: Crest (the highest point of the wave) and Trough (the lowest point of the wave). Show the crest and trough on the paused image. Once the students understand the new terms REWIND the tape slightly (2-3 seconds), then PLAY the video from the previous pause point. During this segment you may want to go over the vocabulary terms Wave Period (the time taken for two wave crests to pass a fixed point), Fetch, Wavelength, and Wave Height. PAUSE the tape when you hear the scientist say, "…wave height at the beach would be 44 feet" and the visual image is a cross-section of the projected wave. Make a note on the board of the new wave height estimation: 44 feet. (The other number on the board is the students', from their on-screen estimation.) Then explain that wave height is the height of the swell in the open ocean. The Wave Face is the height of the breaking wave at its highest point. PLAY the video for 10 seconds and PAUSE it again when you see the graphic of the wave face cross section and you right after you hear the narrator say, "…ten-story building." Point out to them the shelf that triggers the swell and "trips" it, causing it to rise higher than the wave height creating a breaking wave. Remind your students of the two focus questions: How do the oceanographers predict swells? How do the surfers use the scientific information? Discuss student answers and replay tape if necessary. (Correct answers: 5) They use buoys to record the height and distance between swells, which is sent to them via radio & satellite. 6) The surfers look at the pattern of the swells and estimate exactly when to get to the beach for the best waves.)
FAST FORWARD the tape until you see the moon followed by local Hawaii news footage with the newscaster saying, "State civil defense crews…" Provide your students with a FOCUS FOR MEDIA INTERACTION-asking them to answer question 7 on their WaveFocus Organizer: What was the main reason the surfers couldn't surf on January 28? PLAY the video until you hear the narrator say, "…the contest was called off" and you see a black and white image of people on the beach. Field answers from students. (Correct answer: 7) They couldn't get to the waves because the breaking surf was so rough. It was too dangerous.) If students seem lost or answered the questions incorrectly, rewind the tape & play it again. Ask students if anyone understood what the surfer meant when he said the waves had "closed out"? Have students refer to their WaveLingo Organizer and have someone read the definition of Closed Out (when a wave breaks along its length all at once, making it unsurfable).
FAST FORWARD the tape until you hear the coast guard officer say, "…most of them are really good at what they do" and the image is a wide shot of the ocean with a green foreground. Provide your students with a FOCUS FOR MEDIA INTERACTION-asking them to answer question 8 on their WaveFocus Organizer: Why is Log Cabins a good place for giant waves? PLAY the tape until Ken Bradshaw says, "…I could ever image actually." PAUSE the tape. Field answers. (Correct answer: 8) Log Cabins has very deep water (50 feet) and has a very steep, 10-foot shelf, that trips only the biggest swells.) It's hard to imagine a wave of 25-feet being too small, but that's the case in this spot. If students seem lost or answered the questions incorrectly, rewind the tape & play it again. This is a little confusing so you may have to play it again.
FAST FORWARD the tape to an image of a surfer moving from right to left being towed by a jet ski and the narrator says, "A milestone in the history of surfing was set…" and provide your students with a FOCUS FOR MEDIA INTERACTION-asking them to answer question 9 on their WaveFocus Organizer: What did Ken Bradshaw do on January 28, 1998? PLAY the tape until you hear the narrator say, "…minimal damage to property" and the video goes from a close-up of the beach with water retreating into the ocean followed by a fade to black. Field answers. (Correct answer: 9) He surfed the biggest wave ever surfed by a human. Pretty cool.)
(NOTE: This video is available as a streaming video on the Nature Web site at http://www.pbs.org/wnet/nature/database.html. See the "Media Components: Video" section of this lesson for more details.)
(For Day 2 the ideal set up is in a room with access to at least 3 computers and a large work area to do the hands-on activities)
Explain to your students that yesterday we learned about some of the largest ocean waves ever recorded. Who can remember the main causes for the huge waves in the video? (A big storm off the coast of Japan caused: a) extremely high wind speed-65 knots, b) over a very large fetch or distance over which the wind is blowing-1000 miles, and c) the duration the wind is blowing over the area was very long-36 hours.) Next, ask the students what you get when two substances (air and water in this instance) rub together (Correct answer: friction).
So, we learned that wind blowing on the surface of water is the most important factor in wave creation. If there was a boat sitting on the ocean and the wind was creating large swells of 15 feet, what would happen to the boat? Here you can use the chalkboard to draw the scenario using two drawings. Show a cross section of a wave (from left to right: crest, trough, crest, etc. with a boat placed somewhere on the wave) as well as a view from above (show a series of waves approaching the shore and that the wind is blowing from the ocean to the shore). Answers will vary. Some may say the waves will carry the boat towards the shore, some might say that it would depend on the size of the boat. Hopefully someone will say that the boat will move in circular motion. Now, we're going to look at a Web site that shows what happens to a boat on the water (either via LCD computer projection or by having the students in groups at computers or at individual computers in a lab, go to: http://www.pbs.org/wnet/nature/conditionblack/. Remember to bookmark this site or give the students access to the shared Portaportal account). Click on the "High Seas" link at the right of the page. An animation opens describing each part of the wave. Go over each part and ask the students if they recall their definitions.
Once you've gone through the parts of the wave, remind the students of your earlier question (what would happen to a boat on the water where wind has created large swells) and their answers. Click on the number 2 in the bottom right corner of the page. An image appears of a boat bobbing on the water. Have one student read the description. So, while wind will cause the boat to move slightly forward toward the shore, the water particles themselves aren't moving forward. If that's the case, ask the students what do they think is moving forward as a wave approaches the shore? (Answers will vary.) The correct answer is energy being passed to the water from the air through the friction. If the water particles actually moved forward due to the wind, all the water would bunch up on the shore and flood the land!
Now click on number 3. This image shows the pattern of water particles as they are affected by the wind. Explain that the wind affects the wave as the waves move toward the shore, but it also exerts energy downward. Water particles move in a circular motion beneath the surface of the water. Several circles are created which line up beneath the wave as far down as half the wavelength. That's an important fact so ask the students to remember that distance.
Ask the students, "What do you think causes the wave to break on the beach?" (Answers will vary.) Click on number 4 in High Seas and then click on "More" to reveal the second paragraph (the information in the first paragraph has already been covered). Ask a student to read the paragraph. Explain that as a wave approaches the shore the depth of the water decreases. When the water depth is about half of its wavelength, the ocean bottom creates drag or friction with the water molecules at the bottom of the wave. Remember, the circular motion caused by the energy transfer extends to a depth of half the wavelength. The ocean bottom slows down the bottom part of the wave, but the top of the wave maintains its speed and ultimately collapses on itself creating the surf we see at the beach.
Wave Experiment: Now, to demonstrate the action of wind on water we're going to do an experiment. First, set up the experiment in terms of the scientific method:
- Make an observation about the physical universe: waves occur in bodies of water.
- Create a hypothesis: Wind causes waves.
- Make predictions: Wind on a body of water will create waves.
- Test the hypothesis and measure results: Do the wave experiment and record results.
Place a wide, long aluminum pan on a table. Fill it with ¼ inch of water (you can color the water blue or green to make it more visible). Tilt the far end of the pan up slightly with some paper to simulate the shoreline (the water should end just short of the end of the pan).
Use an Asian-type paper fan at the near end of the pan to create wind on the water. Record the results. (Little wave activity should occur.)
Blow air through a plastic straw at the near end of the pan. Record results. (Slight wave activity should be evident.)
Turn on the electric fan and aim it, on low, at the near end of the pan. Record results. (Slight wave activity should be evident.) Turn the fan on medium. Record results. (Moderate wave activity should be evident and some of the water may be displaced farther up the pan.) Turn the fan on high. Record results. (Significant wave activity should be evident and some of the water will be displaced farther up the pan. But all the water will not bunch up at the end and if you look at the edges of the water you can see that the water itself doesn't move forward after the initial influx of air has hit it.)
Based on the hypothesis-wind causes waves-was our experiment a success? (Yes.)
Now, take out the jump rope and place it in a straight line on the table. Aim the fan, on high, directly at the jump rope. Record results. (Assuming you have a fairly heavy piece of rope, nothing should happen.) Ask two students to hold each end of the rope. Have one student whip the rope while the other student holds it steady. Record results. (A wave moved from one end of the rope to the other.) Ask the students what caused the wave? (The motion of the arm caused the wave through energy transfer.) Is this consistent with out hypothesis (wind causes waves)? Make a correction to the hypothesis: Energy transfer causes waves, or wind causes waves on water).
Break the class up into 4 groups. Hand out the map of Southeast Asia printed from the Web site: http://www.map-asia.com/map-southeast-asia/map_seasia_polstd.htm Distribute to each group a piece of poster board and colored pens. Inform each group that they are world-renowned oceanographers who have been approached by the World Surfing Federation to come up with the site and dates for their 2004 world championship. The only parameter is that the tournament needs to take place in Southeast Asia. Have each group decide on a part of Southeast Asia and a time of the year where they think there will be excellent surfing. Students should discuss with each other the factors they have learned about (wind speed, fetch, ocean bottoms) that will affect where the biggest waves in Southeast Asia will be. Students can also use the Internet to help them research. A selection of sites is available in the ConditionBlack Portaportal account (also see "Resources" section at the end of this lesson). Students should also be encouraged to research information on their own.
Explain that the last time the WSF held its tournament in Southeast Asia, they chose the north shore of Siquijor Island in the Philippines. (Show the Web site "Map of the Philippines" in the Portaportal account. Siquijor is located at approximately 9 degrees longitude & 123 degrees latitude just north of the large southern island of Mindanao.) Can anyone predict what the surfing conditions are like on the north shore of Siquijor? (Answers should be unanimous: Bad surfing conditions as there is very little open ocean, or fetch, for wind to create large waves.) Now you can show students the pictures of the surf conditions on the north shore of Siquijor Island, found in the appendix.
Each group will write a letter to the WSF explaining why they have chosen their location and they should use the poster board to create a display to help build their case. This can be done over the course of several days incorporating the research as homework. By Friday each group should be able to present their proposal to the WSF.
Video is a powerful instructional tool. Not only televised video for use in the classroom, but also original video that you as an educator, along with your students, can create. This lesson involves a film that was created with the help of students at the Trevor Day School in Manhattan. Our goal was to create a video that incorporated the ideas found in the lesson, in a fun, hip and easily recognizable and identifiable format: a TV news show. Based on what they had learned about waves, the students were given the freedom to design the newscast segments, create interview questions for the guest, and develop a commercial about waves. The students were involved in the writing, filming and editing process.
The guest on our newscast is Mike Nelson, a surf photographer and filmmaker based on Long Island where he co-owns a surf shop in Long Beach. The video includes some of Mike's photography and film work (used with his permission) as well as a theme song by the Brooklyn-based Broadband (also used with their permission). Make sure anytime you use music or graphic images in a project you obtain the right to do so from the copyright owner, especially if you plan on posting your projects on the Internet. The interview with Mike Nelson is the key component of the video. The questions focus on the real-world applications of the science discussed in the Nature episode and the lesson. As a surfer, surf photographer and filmmaker, Mike Nelson uses science on a daily basis to predict wave activity. If the indicators for high surf are good, and he knows that a tournament will happen-he goes to cover it. The recording session for this video hinged on the wave conditions for a tournament in Mexico which actually delayed our production schedule as the surf was up!
If you are considering making a video with your students, there are many ways to approach it. Your students could study maritime information including meteorological reports, tide schedules and maritime buoy readings to predict what the waves will be like at a specific time and day and then go film the beach that day to see if the prediction is accurate. You could focus on a different type of wave, such as a fjord tsunami where water displacement is caused by a huge piece of an iceberg falling off into the water. Simulate this with varying size rocks being dropped from a set height into a lake or pool of water and then measure the wave statistics. Or, you too could interview someone such as a surfer, an oceanographer, a meteorologist, etc.
Whatever you do with the video, make sure you have fun with it!
ART & MUSIC
There are many options for wave-related art projects. If you have access to the beach you could introduce the idea of landscape painting and have the students do a landscape painting of the beach. To prepare them, you could have them look at some of these examples:
Introduce your students to surf music. There are dozens of bands that over the year have played this special brand of guitar-driven, sometime instrumental music. Some of the most famous surf musicians are Dick Dale and The Ventures.
A poem about waves. Formed by wind far, far away. Crashing on the beach. (A wave haiku!) Waves make a great topic for poetry. They are rhythmic and serene and violent all at the same time. For some examples you could look here: http://www.magicsurfbus.com/surfspeak.htm. Or, the students could write a story about an impending tsunami-how will it affect the nearby communities?
Beach erosion and shoreline changes are difficult problems faced by many communities throughout the United States. Students could examine the effects of erosion not only on the people who live near the water, but also how it affects the local ecosystems.
Have your students research the worst tsunamis in history. There is much information on the Internet related to tsunamis such as http://www.geophys.washington.edu/tsunami/intro.html.
Students could also research the history of surfing. Surfing has a rich and fascinating history. It happens all over the world (even on the Great Lakes! http://www.surfingvancouverisland.com/surf/newgard/)
- Ask a surfer, meteorologist or an oceanographer to come in and speak to the class.
- Students can get involved with the Surfrider Foundation who work to protect our oceans, waves, and beaches.
For more sites see the Portaportal ConditionBlack account.
Discovery Channel: Blue Planet-Seas of Life
This interactive site lets students change different weather variables in order to affect the surfing conditions at the beach. You will need the Macromedia Flash plug in to use this site. (http://www.macromedia.com/shockwave/download/
National Data Buoy Center
This site plays a crucial role as surfers attempt to predict wave activity throughout the US and parts of Europe. Buoy readings give information such as wave height, wave period, wind speed, and water temperature.
National Geographic Wave Simulator
Students can change the wave height, wavelength and wave period to create different sized waves. You will need the Macromedia Flash plug in to use this site.
Naval Meteorology and Oceanography Command
The Naval Meteorology and Oceanography Command's mission is to collect, interpret and apply global meteorological and oceanographic data and information. This site contains many useful definitions.
Office of Naval Research
The main causes of tsunamis are explained and demonstrated.