Converting Nautical Units

By Vicki Howell, [email protected] Menominee High School

Target Grade: H.S. Chemistry, Environmental Science and/or Math

Lesson Overview: Students will practice converting units using a method known as factor label or dimensional analysis. The examples will emphasize nautical units of measure. Converting units is an important skill in math and science. This activity will allow students to practice this skill while being introduced to some new units/vocabulary that relate to maritime transportation.

Sources Consulted www.unitconversion.org factmonster.com http://techalive.mtu.edu/glmri/index.htm

Learning Objectives: After this lesson, students will be able to: 1. Work effectively with various units of measure used in maritime travel—be specific--- what units of measure?

2. Use conversion factors to convert nautical units

3. Compare and contrast units such as the geographical mile v. nautical mile, fathom, cable length and knots.

State Benchmarks Addressed:

Students collect and explore data, organize data into a useful form, and develop skill in representing and reading data displayed in different formats. (Collection, Organization and Presentation of Data)

Students will apply their understanding of number systems to model and solve mathematical and applied problems.

Focus Question: How do geographical units compare mathematically with nautical units and how can they be converted one to the other?

Materials: List of conversion factors (attached) and access to the internet Calculator Practice Sheet (attached)

New Vocabulary: Nautical Mile: unit of length used in maritime and aviation travel, 1.1508 geographical miles Maritime: having to do with the sea Fathom: the length of rope a man can extend from open arm to open arm….6 feet. The rope was lowered into the sea to measure depth. Cable length: length of a ship’s cable, about 600 feet Knot: measure of speed on water

Procedure: 1. Review the topic of Maritime Transportation and the Great Lakes using Michigan Tech’s website… ( http://techalive.mtu.edu/glmri/index.htm) 2. Discuss how maritime travel has some measurement units that are unique to that mode. 3. List the various nautical units of interest and define them. 4. Construct conversion factors using new information. 5. Practice converting using the factor label method (dimensional analysis) using our new conversion factors.

Assessment: The students will be assessed as to their ability to answer the preceding questions and engage in discussion earlier in the lesson. Practice Sheet: Factor Label with Maritime Conversions

Name:______

Maritime Conversion Factors: ** 1 fathom = 6 feet ** 1 cable length = 600 feet ** 1 nautical mile = 10 cable lengths ** 1 nautical mile = 6,076 feet ** 1 nautical mile = 1.1508 geographical miles ** 1 knot = 1 nautical mile/hour

Use the conversion factors above to convert the following units. Show all of your work! 1. How many feet in one geographical mile?

2. If you are traveling 55 geographical miles per hour how many knots are you traveling?

3. How many cable lengths are 1500 fathoms?

4. It is 57 geographical miles from Menominee, MI to Green Bay, WI. What would that value be in nautical miles?

Answers to Questions 1 – 4 on Practice Sheet:

1. 5,279.8 feet

2. 47.8 knots or nautical miles/hour

3. 15 cable lengths 4. 49.5 nautical miles