The students will need protractors, compasses, rulers and some example charts beyond the ones below and

The MapQuest.com map of Charlestown, MA and Map Reading Activity.

The accompanying Chart 1 and Chart 2 for Take Home Test.

The accompanying Take Home Test Solutions.

Procedure

Opener:

Bring out some nautical charts (from anywhere) and other types of maps (street, topographical, etc.) and ask the students to start identifying differences between them. Make sure that they notice the: compass rose, latitude and longitude lines, loran lines (if your chart has them), note to mariners and other features.

Development:

Explain how latitude and longitude are divided into degrees and then minutes. One minute is taken as 1 nautical mile (=1.16 regular miles) when located near the equator. Explain how the earth has a magnetic field and that the "magnetic" north pole is different from the "true" or actual north pole. The compass rose has both the "magnetic" and "true" compasses on it and that a compass on a boat uses the magnetic one. In practice, this can make a huge difference in where you end up traveling. Continue with an explanation of how vectors are used in estimating the actual direction of travel since it is the resultant vector of the boat's velocity, water current and other factors. All these velocity vectors add up in order to determine the actual velocity vector of travel. Show the students how the the directions on the compass measures angle differently than how math and physics measures angle. THIS IS IMPORTANT! Since the latitude and longitude lines are in the N-S and E-W directions, a protractor can be used to estimate the angle of a resultant vector. Everything can be estimated by utilizing a compass (the tool), a protractor, straight edge and parallel straight edge. For a more analytic and accurate approach, utilize properties of triangles and trigonometric functions.

Closer:

Close out with taking a bearing off landmarks and triangulating to determine a position.

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