Latitude and Longitude

latlong

Build an Earth model that shows the concept of Latitude and Longitude
Grades 4-6

It is believed that the art of navigation originated about 8000 years ago in the Mediterranean basin.  The science was slowly developed and is replete with famous names of early navigators such as Columbus, Magellan, Drake, Cook and others.  One of the earliest accounts of recorded navigation comes from a Greek navigator, Pytheas of Massilia.  Pytheas embarked from the Mediterranean about 325 BCE and sailed to England and Scotland and then to Thule, Norway, and the coast of Germany without the bare essentials of navigational equipment.  Today yatchsmen can sail around the world alone with the aid of only a small electronic Global Positioning System.  The concept of latitude and longitude are fundamental to mapping and navigation.

Preparation
Gather Earth imagery pictures to illustrate the model of a spherical Earth.  Use a class globe as a model for this activity, if available. Material for making an Earth model may be desired.

Procedure
The teacher should prepare a short class discussion on what our world looks like from a distance (NASA photographs and others of Earth imagery are readily available on the internet). The students should be asked how they would model a way to tell where they were on the Earth.

The teacher should define the terms latitude and longitude for the students and show the students how planes intersecting the Earth model define these concepts, noting how they are measured angularly from a defining location such as the Equator or North/South Poles.   Important lines of latitude and longitude should be discussed.

Students will use the basic geometric shapes from GollyGee Blocks to develop a 3D model of the Earth and then pass planes through the Earth to describe the concepts of latitude and longitude.

Start the scene by dragging a sphere into the scene.  Texture the backgrounds with the sky and cloud textures.  Use the marble texture on the Earth.  Note that the polygon rendering of the sphere when textured provides convenient latitude type lines.

Select the sphere again and use the Stretch tool to collapse the sphere into a spherical plane.  Using the Move tools (Scale, Lift, Lateral Move) move the plane to intersect the globe model  parallel to one of the lines on the sphere.  The planes can be duplicated and placed so as parallel.  Rotate the planes copied vertically and move to intersect the Earth model perpendicular to the latitude planes.

Color or texture the latitude and longitude planes.  Save and print the scene.

This lesson can be combined with one on parallel lines or angular measurements in mathematics.

Evaluation
Teacher reviews printouts or on-screen development to check concept grasp.

Using a classroom globe, have students research and point out important lines of latitude and longitude (e.g., Equator, Prime Meridian, Tropics of Cancer and Capicorn, North Pole, South Pole, 180th Meridian, Arctic Circle, Antarctic Circle).

Evaluate a written description of the activity.

Extensions
Have students create an Earth Model and develop planes of latitude and longitude to intersect the Earth.

Students can make up there own measurement system for navigation.

Pick different locations in the world and structure a contest based on time and accuracy

Assign a report on an important navigator and discuss in class.

Develop scenes that illustrate the development of the science of navigation (instruments/maps).

Tips
The overhead camera is very useful in aligning the intersecting planes on the Earth model.  Color the planes to make the work easier.  Use the Zoom tool to obtain better perspective while developing the model.

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