The image is of the APH Tactile World Maps.

Shape of the Earth with 2-D and 3-D Models: Practicing Tactile Graphics

In this activity, students consider how a model of the 3-D Earth can be shown in 2-D on a tactile graphic, and why models, though useful, have limitations.

Students practice tactile diagram reading skills as they  describe how a two-dimensional model can represent the 3-D Earth.  Strengths and weaknesses of these models (and models in general) are discussed.  This activity is most appropriate for students who have at least a rudimentary understanding of tactile graphics. 


tactile globeProcedure

Part I:  Tactile and Visual Globe

  1. Hand out an APH Tactile and Visual Globe to each student.  Students will begin by observing the tactile and visual APH globe.
    • Ask: “What shape is this globe?”   – Round 
    • Ask: “Why is it round?”  – Because the Earth is round.  
  2. Tell the students that the tactile dot represents their location on Earth. 

Discuss your location and the continent on which you live briefly incude adjacent oceans.

Part 2:  APH World Maps – Atlas 

Leaving the globe nearby for use, pass around the APH World Maps (one to each student).  For more detailed info on working with students on tactile graphics please see the following blog post:  Tips for Reading Tactile Graphics in Science with a Focus on State Assessment

A. The title 
B. The key
C. Deciphering the tactile graphic

Ask the students to find North America on the map.  Give them a few minutes to do so. Some students may need verbal prompting or hand-under-hand assistance to find North America but allow students to work toward finding the locations independently.  

Once all students have found North America, have students find  the ocean to the west of North America (tell the students this is left on a map). Have students raise their hands with the answer so that all students have found it on the key before a student is chosen to answer.

Part 3:  Tactile Globe and APH Tactile Map

  1. Hand the students back the tactile globe and have them find North America and the ocean to the west.  Ask: “What ocean did we determine this is?”  (The North Atlantic)
  2. Have students follow the North Atlantic Ocean west and find the continent to the west.  Ask students if they recognize the shape.  Tell students that this is Asia.  
  3. Discuss the 3-D nature of the Earth and the 2-D nature of the map.  Students should comprehend that the North  Pacific wraps around the Northern hemisphere and therefore is west of North America but East of Asia.  Explain that the 2-D map is not able to show this.
  4. Take questions as students have them.
  5. Complete steps one through three of Part 3 above considering the South Pacific intead of the North Pacific. It is located to the west of South America and to the East of Australia on the map. Have students tind these locations if time allows. Discuss using the globe as well. 

Part 4:  Closure – Models

Students will better understand that models have strengths and weaknesses from this activity.   Have students, working in groups of 2 if possible, compose a list of strengths of each model and a list of weaknesses. 


NGSS Standards

Middle School: Space Systems

Middle School Engineering:  Systems and System Models

Science and Engineering Practices – Grade 2: Developing and Using Models

By Laura Hospitál

Collage of practicing tactile graphics by teaching students with visual impairments about the shape of the earth

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