Activity

# 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.

### Preparation

• Mark your location on the globe with a tacile dot on each globe.

### Procedure

#### 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
• Ask students when they are using a tactle graphic, what should they look for first?  (The title)
• Have students find the title “The World”  (located on both the right and left hand pages of the map)
##### B. The key
• Ask: “What should you look for next?”  (The key)
• Ask:  “Is there a key?”  (Yes)
• Give students a few minutes to read over the key (2-5 minutes, depending on reading levels)
• Ask:  “What information is this key giving us?”  (The oceans)
• For the following question, students will refer back to the graphic itself.  Ask:  “Why do you think this key includes the oceans only and not the continents”  (The continent labels fit on the map without shortening them.)
##### C. Deciphering the tactile graphic
• Finding North America

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.

• Finding the North Pacific

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.

• Have students complete the above 2 steps but this time ask them to find the ocean to the east of Asia.  Again have all students find the continent and ocean before allowing a student to answer.  Students should determine that this is also the North Pacific Ocean.
• Students may be a bit puzzled as to how the North Pacific Ocean can be on the left and right sides of the world map.  Ask students to consider how this can be but have students who clearly know the answer wait until others have thought about it.

#### 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.

### Variations

• This activity could also be completed with a large print map of the world and the APH globe for large print students.
• This lesson could also be used in a geography class.

### NGSS Standards

#### Middle School: Space Systems

• ESS1.B: Earth and the Solar System: The solar system consists of the sun and a collection of objects, including planets, their moons, and asteroids that are held in orbit around the sun by its gravitational pull on them. (MS-ESS1)

Middle School Engineering:  Systems and System Models

• Models can be used to represent systems and their interactions. (MS-ESS1-2)

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

• Modeling in K–2 builds on prior experiences and progresses to include using and developing models (i.e., diagram, drawing, physical replica, diorama, dramatization, or storyboard) that represent concrete events or design solutions. Develop a simple model based on evidence to represent a proposed object or tool. (2-LS2-2)

By Laura Hospitál