Teacher Resource Guide Preferred Activities

Transcription

1 Teacher Resource Guide Preferred Activities Complete Teacher Guide available at Also available on Seamobile Resources USB Education Outreach With Generous Support from the Maxwell H. Gluck Foundation

2 12 Finding Your Way Background Finding Your Way How do we know where we are and where we re going? Background Beginnings of Navigation Almost anyone can travel without getting lost, as long as they know where they are, where they want to go, and the path between. On land, a person can use landmarks and physical descriptions: Take the path uphill to the big rock that looks like a bear. Find the three trees growing from one stump and walk past it until you can see the waterfall. This method doesn t work well on the ocean: Turn left at the third wave, and go until you see the big fish with the red stripes. Turn right and go until you reach England. The earliest sailors probably kept close to shore, using the land s physical features as landmarks to steer by. This worked well for short voyages, since food, water, and shelter were always close by. Of course, this approach worked only when sailing during the day, and made for very long trips. As sailors made maps of their travels, it became evident that some places could be reached faster by sailing in a straight line, rather than hugging the shore. But this would mean leaving sight of land and any recognizable landmarks. Some of the early methods used for navigating across open waters involved using the sun, moon, and stars. People had long been traveling on land, getting from place to place by traveling in directions with some relationship to these celestial bodies. With the invention of the compass, people could find their direction even when they couldn t clearly see the sky, day or night. These methods were applied to ocean travel; if a sailor knew another port was west of his home port, all he had to do was follow the path of the sun or his compass. Unfortunately, winds and currents further complicated this process, as they could easily and subtly alter the heading and leave the traveler lost. Through generations of experience, many early coastal cultures became familiar enough with their local currents and winds to actually be able to navigate them over moderate distances away from shore. Long distance voyages and trips to little-known areas, on the other hand, were still problems.

3 Latitude and Longitude The concepts of longitude and latitude have been used now for roughly 2,000 years. Lines of latitude run around the globe and measure the degrees north or south of the equator. The equator is given a value of zero (0) degrees \longitude. Lines of longitude run up and down the globe and measure the degrees east or west of a line called the prime meridian, which passes through the original location of the Royal Observatory at Greenwich, near London, England. The prime meridian is given the value of zero (0) degrees latitude. When the latitude and longitude are given, the precise location of a point can be located on an imaginary geographic grid. When latitude and longitude are given on a map, latitude is always written first. Degrees of latitude and longitude are further divided into minutes and seconds. There are sixty minutes in one degree, and sixty seconds in one minute. One of the earliest tools used to aid mariners in determining latitude was the astrolabe. This instrument consisted of a metal disk, graduated in degrees, with a moveable sight. The astrolabe was held vertical by a plumb bob, and the navigator (with the help of two other people) adjusted the sight until it was in line with a star. The degree measurement was then looked up on charts and tables, which gave the latitude of the ship. Modifications of this instrument by scientists, including Sir Isaac Newton, led to the development of a new device called a sextant. The basic design of the sextant has remained virtually unchanged for over 200 years. Determining longitude was a bit more difficult. Many attempts were made at finding ways to determine longitude while at sea, but none were very successful. In 1735, John Harrison developed the chronometer an extremely accurate timepiece that was used to maintain a time reference to the prime meridian. This instrument allowed navigators to compare local time to time at the prime meridian. The time difference between the navigator s present position and the prime meridian told them their position. At last, a simple and reliable method of determining longitude! It was now possible to accurately determine position anywhere on the ocean, provided you had good charts and tables and an accurate chronometer. Sailors navigated well into the 20th century using these techniques until the advent of more sophisticated electronic and radio methods. New Technologies Today, radio beacon towers are located all along our coastlines, constantly sending out powerful identification signals. These signals can be picked up by sea vessels as far as several hundred miles away. The Radio Direction Finder (or RDF) on board a ship can be tuned to receive these broadcast signals. The beacon s I.D. signal, in Morse code, allows the navigator to look on a map and find the radio beacon that is sending that particular signal. The RDF is also used to determine the direction or heading from which the signal is being sent. A second radio beacon signal is then needed to pinpoint the exact location of the vessel. This entire process is known as triangulation. (See the activity Getting Your Bearings for more information.) The Global Positioning System (GPS) is a satellitebased radio navigation system developed in the 1970 s by the Department of Defense. GPS allows land, sea and airborne users to locate their three-dimensional position anytime, anywhere in the world. The GPS uses an array of satellites continuously sending high-frequency radio signals; at any given time from any point on earth, there are six or more GPS satellites orbiting above you. GPS receivers like cell phones and car navigation units are used to pick up these signals. These satellite signals contain information about the exact position and clock reading on board. The GPS unit compares the signal departure times and arrival times, and the time delay is used to calculate the distance between the satellite and the receiver. The GPS determines the distances from three or more satellites and uses this information to find the closest possible location of the use, usually within a few feet. Finding Your Way 13

4 Finding Your Way Map Building pre-visit Materials large wall map* sets of activity pieces with map coordinates* tape Map Building worksheets rulers (one per student) *materials found in Seamobile Teaching Kit Activity Time 40 minutes Process Skills Communicating Comparing Ordering Connections Math Geography Map Building Students will develop their own map based on their knowledge of latitude and longitude and discover the many things that make up an ocean ecosystem. Procedure 1. Review the concepts of geographic grids, latitude, and longitude. 2. Explain to the students that, over the years, the Seamobile research area has been mapped by many different people for different reasons. Before we can study the area, one concise map must be developed so that we know where everything is. It will be the students jobs to piece together the information from the previous investigators. 3. Divide students into teams and distribute one set of four map pieces to each team. Each piece represents an ocean feature (kelp forest, shipwreck, sewage drain, etc.) In addition, each team (or student) should receive a map worksheet depicting the area surrounding the San Pedro Channel. 5. Each team representative will place their team s map pieces on the wall map using tape. In many cases, students can confirm the location of their map piece by looking on the large map for a similar symbol. 6. Discuss what their pieces represent and why these various things are found in our oceans. Extension Many of the features described in this activity have symbols which are used on ocean maps. It is important to understand that there is more than one symbol that might be used for a feature, and that some features may not be marked on a particular map. The list of symbols on the following page can be used to double-check latitude and longitude readings on the wall map at the end of the Map Building activity. 4. Using the latitude and longitude coordinates on the back of each individual map piece, students should locate the proper positions of their pieces on the map worksheet. 14

5 15Map Building Student Worksheet

6 Common Nautical Chart Symbols Map Building Chart Symbols Shipwreck Kelp Bed Fish Haven Sewer Line Oil/Gas Platform Dump Site Radio Beacon Lighthouse Buoy SOURCE: Chart No. 1 United States of America, Nautical Chart Symbols, Abbreviations and Terms, 1990, Department of Commerce, National Oceanic and Atmospheric Administration; and Department of Defense, Defense Mapping Agency. 16

7 Getting Your Bearings Students will use rulers and an understanding of compass readings to identify the location of five possible Seamobile study sites through a process of triangulation. Students will then determine headings to each of these sites. Introduction There are various ways to determine your position in the open ocean. One method is to use a Radio Direction Finder (RDF). Radio signal transmitters (beacons) are located along coastlines and send signals that can be picked up by the RDF device on ships at sea. The radio signal can then be used to determine the compass bearing from the radio beacon to the ship. By determining the bearings from two different radio beacons, navigators can determine their ship s position by examining where the bearing lines intersect. This method of pinpointing the location of an object based on two different bearings is called triangulation. In this activity, the Seamobile has scouted five possible study locations and has taken radio beacon readings at each of these locations. Using triangulation, the students will plot the location of the Seamobile and the five study sites. Then they will plot headings from the Seamobile to each location. Procedure 1. Divide the class into teams of 3 or 4 and distribute materials to each team. Introduce the concept of triangulation and discuss the use of radio beacons and corresponding compass headings to determine location. Distribute the Student Information Sheet and data table for this activity. 2. Locate the Seamobile on the chart through triangulation. Use the given radio beacon readings as compass headings to plot. For example, if radio beacon one (RB1) is 90, this translates into a compass reading of 90 degrees. Follow the steps as described on the Student Information Sheet. 3. It is helpful to work through the triangulation method for the Seamobile location step-by-step with the entire class. 4. Once students have identified the location of the Seamobile, they should proceed to identify the locations of each of the study sites, using the radio beacon readings in the data table for each site. 5. After the study sites have been located, the students can determine the compass heading from the Seamobile to each study site. Again, you should work through the first heading (for site A) with the entire class. Follow the steps described in the Student Information Sheet. 6. Remind the students that because they are using a circle of 360 degrees to define their direction, they don t need to add a direction indicator (like S or NE). These direction designations are redundant for this method. 7. Ask students to double-check their locations by using the latitude and longitude readings from the answer key. Materials laminated desk map* (one per team) parallel ruler* (one per team) overhead marking pen* (one per team) Getting Your Bearings Worksheet *materials found in Seamobile Teaching Kit Activity Time minutes Process Skills Communicating Comparing Ordering Connections Geometry Geography Teaching Tip: You may wish to use an overhead transparency to help demonstrate triangulation to the entire class first. Teaching Tip: A quick check to see if students were able to correctly identify the location of the Seamobile is to look for a nearby depth reading of 204 fathoms on their map. If the intersection of the bearing lines is within a quarter diameter of this point, students are on the right track! Go to org/outreach to view a slide show demonstration of triangulation. Getting Your Bearings pre-visit Finding Your Way 17

8 Student Information Sheet Getting Your Bearings The triangulation process described below will help you find the location of sites on ocean and help you figure out what direction you need to travel to get there. Getting Your Bearings Student Information Sheet To locate a site: 1. Locate the two radio beacons (RB1 and RB2) and the compass rosette on your map. 2. Begin by looking at one radio beacon reading (RB1) and marking the heading on the compass using the overhead marking pen. Use the parallel ruler to draw a straight line connecting your heading mark and the center of the compass. 3. Place the bottom edge of the parallel ruler along the compass line you just drew. While holding the bottom of the ruler in place, move the top half of the parallel ruler up until the ruler edge touches the center point of RB1. Use the marking pen to draw a line on the map along the top edge of the ruler. Be sure to hold the ruler so that it does not slide. 4. Remove the ruler - you have just recorded your first radio beacon heading! This tells you that the location is somewhere along that line. To pinpoint the site even more, you ll need another heading (like RB2). 18

9 Student Information Sheet Continued 5. Repeat steps 2 through 4 for RB2. The line you draw in step 4 this time should intersect the first line. If not try these steps again. 6. Circle the point of intersection and label it. Repeat these steps to find the other sites. To Find the Heading 7. Place the top edge of the parallel ruler so that it connects the Seamobile location (SM) and a study site. While holding the top part of the ruler in place, lower the bottom half of the ruler edge until it touches the center of the compass rosette. Draw a line along the lower edge of the ruler, passing through both sides of the compass rosette. 8. To choose the correct compass reading, look at the direction you would take to get to the site from SM. If you are heading north, choose the compass reading on the north (top) side of the compass; if you are heading south, choose the south (bottom) reading. Record your heading on the data sheet. 9. Repeat these steps to find headings for the other sites. Student Information Sheet 19Getting Your Bearings

10 Student Data Sheet Getting Your Bearings Record the headings for each site. Getting Your Bearings Student Data Sheet SITE Seamobile site A site B site C site D site E RB RB Mark the approximate location of each study site on the map below. Heading to site from Seamobile 20

11 Answer Key SITE Seamobile site A site B site C site D site E RB RB Getting Your Bearings Heading to site from Seamobile latitude longitude Answer Key 21Getting Your Bearings

12 Guided Practice For using a Dichotomous Key - Odds and Ends activity Classifying Creatures Odds and Ends pre-visit Key Concept: Students are introduced to a common method of scientific classification called the dichtomous key. They will use this method on a collection of everyday items. The goal of this activity is NOT to identify these objects, but rather to use a dichotomous key correctly. Background: Scientists use keys to help identify and classify plants and animals. By organizing specimens based on similar characteristics, scientists can better understand how these species might be related to each other on an evolutionary level. Keys can come in different formats - some are used to identify organisms into larger categories, such as kingdoms or phyla, and other are used to distinguish among closely related species. A dichotomous key presents the user with a series of positive/negative statements relating to distinct characteristics of the specimen.( The animal has a backbone/ The animal does not have a backbone ). These statements are sometimes referred to as couplets. The couplet is usually an either/or choice. The specimen is correctly identified when one makes the appropriate choice for each set of characteristics in a series of consecutive steps, similar to a flow chart. Procedure: 1.) Discuss with students different ways of grouping objects. Ask why it is important to group objects. You might introduce a dichtomous key as one way of grouping and identifying things. Introduce the term dichotomy (division into two parts, groups or classes) and show how this is important in this kind of classification scheme. Example: The people in your classroom can be grouped into categories of clothing. One couplet for this might be: People who are wearing a blue shirt. People who are not wearing a blue shirt. 2.) Divide the students into teams of two or three and give each team a bag of Odds and Ends, the Odds and Ends Worksheet, and a dry erase marker. 3.) Students should choose one item from the bag and follow the key in order to identify the object. After making the appropriate choice in each couplet, the team will follow the directions on the right hand side of the key until they have identified the object with a particular letter. Students can write the object name next to the appropriate letter on their worksheet, or copy this information into a notebook. 26

13 27 More Information - for using a dichtomous key - Odds and Ends activity Teaching Tip: Students often switch their items as they proceed through the key, choosing an item that matches the positive statement. For example, a student classifying a paperclip, after the statement Object not made of metal, might drop the paperclip and pick up a toothpick since it makes the statement true. Ask students to close their bag after choosing an item. The bag should remain closed until the group has completely finished identifying the object. Materials: Odds and Ends activity set (contains 10 small bags) Each small bag contains 11 items: - small metal paperclip - large metal paperclip - plastic coated paperclip - wooden clothespin - toothpick with plastic fringe - small sponge - metal jack - garden hose washer - penny - plastic straw - pencil top eraser Odds and Ends Student Worksheet (10 laminated copies) Odds and Ends More Information Activity Time: 30 minutes Process Skills: Comparing Ordering Categorizing

14 Odds and Ends - Student Worksheet In this activity, you will use a dichotomous key to sort some everyday objects. How to Use This Key 1. Choose one item from your plastic bag. Close the bag. 2. Begin by reading the first set of choices, called a couplet. 3. Decide which statement of the pair best describes your item. 4. Follow the directions on the right hand side of the key. 5. When your choices bring you to an object letter, write the name of the object on the blank line. 6. Repeat with a new object until your team has identified all 11 objects. 7. Compare your answers with the Answer Sheet when done. Example: 1. Living Go to couplet 2 Not living Go to couplet 3 2. Roots Object D Tree No roots Go to 3 choices directions 1. Object made of metal Object not made of metal Go to couplet 7 Go to couplet 2 Odds and Ends Student Worksheet 2. Wood Not wood 3. Plastic tip No plastic tip 4. Rubber Not rubber 5. Pointed Not pointed 6. Rectangular shape Tube shape 7. Painted Not painted 8. Flat Not flat 9. Object copper color Object silver color 10. Greater than 4 cm Less than 4 cm Go to 3 Go to 4 Object a Object b Go to 5 Go to 6 Object c Object d Object e Object f Go to 8 Go to 9 Object g Object h Object i Go to 10 Object j Object k Centimeters 28

15 A Key to California Marine Shells Students will use a dichotomous key to identify a collection of shells from local marine animals. 29 Procedure 1. Divide the students into teams of two or three. 2. Give each team of students a set of unidentified marine shells from the Teaching Kit 3. The student worksheet describes how the key should be used. When students have finished identifying the shells, they may check their answers on the answer sheet provided. Extensions Ask students to create a simple diagram that shows how they grouped the shells. Remind the students to describe the characteristics at each branch point. (See sample below) TWO PARTS SHELLS ONE CONTINUOUS PART ROUND OR??? CIRCULAR CLAM Materials Set of marine shells* (one per student team) A Key to California Shells worksheet *materials found in Seamobile Teaching Kit Activity Time 30 minutes Process Skills Observing Comparing Ordering Categorizing A Key to California Marine Shells pre-visit Classifying Creatures

16 30 Student Worksheet A Key to California Marine Shells A Key to California Marine Shells Student Worksheet The dichotomous key will allow you to identify 8 shells from Southern California. Follow the directions below to correctly identify each species. How to Use The Dichotomous Key 1. Choose one shell to start with. 2. Place your shell over the purple box that says Shells. 3. Notice that two curved arrows are extending from the purple box. Below each arrow is a red box. Choose the red box that best describes your shell. 4. Next you will choose the blue box that best describes your shell. 5. Continue choosing boxes that describe your shell until you reach a green box - i.e. Abalone. 6. After you have identified each shell, check your answers on the answer key. 7. See example below. EXAMPLE Two Parts Shells One Continuous Part Mussel Teardrop Shaped Round Clam = Clam

17 A Key to California Shells Dichotomous Key Two Parts Mussel Teardrop Shaped Round Clam Olive Snail Shells One Continuous Part One Opening More than one opening Smaller than 6 CM Use Ruler Below Larger than 6 CM Four or More Holes Less than Four Holes Purple Gray Brown Orange Use Ruler Below More Than 8 CM Less Than 8 CM Abalone Keyhole Limpet Wavy Top Turban Snail Chestnut Cowry Kellet s Whelk Centimeters

18 31 Answer Key A Key to California Marine Shells CLAM OLIVE SNAIL (olivella) MUSSEL KELLET S WHELK CHESTNUT COWRY KEYHOLE LIMPET A Key to California Marine Shells Answer Key ABALONE WAVY TOP TURBAN SNAIL