Tech Directions - September 2007 - (Page 15)

60° 2. Students will use the resources, materials, and equipment identified in this brief and by the instructor to fabricate the dome. 3. Students must individually complete dome activity report sheets. Hubs A, B, and C Geodesic Dome Activity In this activity, you will explore the basic math, science, and technological principles related to the design and construction of geodesic structures. You will also investigate the advantages and disadvantages of dome construction. During the activity you will have an opportunity to analyze the needs of an identified dome. You will then design and build the necessary hubs and struts to form the triangles for the dome’s final assembly. 72° Hub D Fig. 1—Hub assembly jigs 3. Effectively use math, science, and technological principles and techniques to fabricate a geodesic dome. 4. Perform the necessary calculations associated with an identified dome’s construction. 5. Complete the production of the dome to stated specifications. 6. Locate, assess, and report on information from the Web and other information sources. Potential enrichment activities include: conducting an overview of a simple geodesic structure based on the use of simple modeling materials, such as rolled newspaper and masking tape, performing the necessary calculations to create a dome of a student’s own design, and developing plans, tooling, and materials needed for the construction of a three-frequency geodesic structure. Procedure 1. Before performing any other tasks, read these instructions. 2. Complete Geodesic Dome Activity Sheets 1 through 8. 3. Determine the total amount of materials necessary to fabricate and assemble the dome. 4. Determine the necessary jig and fixture requirements, form the required groups, and fabricate jigs and fixtures from 1/2" and 3/4" plywood for Hubs A, B, C, and D. (See Fig. 1.) 5. Fabricate the required hub sides from 3/8" plywood and hub spokes from 3/4" plywood. (See Fig. 2). You will need 5 of Hub A, 5 of Hub B, 10 of Hub C, and 6 of Hub D. (Note: Instead of 3/4" plywood, 3/4" pine, poplar, etc. can be used to make the dome hub spokes. These materials increase fastener and adhesive strength, but often split easier than plywood if the dome structure is placed under a load. Builders may want to conduct tests to see which material would be best suited for hub spokes.) 6. Drill a clearance hole for a 1/420 stove bolt, on center, 1-3/8" from the appropriate ends of the hub spokes. 7. Glue and screw or nail the hub sides and spokes together. 8. Fabricate Struts A and B from 3/4" plywood. You will need 30 of Strut A, 3/4" × 2-1/2" × 44-1/2" long, and 35 of Strut B, 3/4" × 2-1/2" × 51-1/2" long. Drill a clearance hole for a 1/4-20 stove bolt, on center, 1-3/8" from each end. 9. Paint each of the struts, hubs, and arms using a color legend simi- Left 8 14-1/2 Right 4 Need 10 of each Need 20—2-1/2" × 6-1/2" spokes, 10—2-1/2" × 14-1/2" spokes 4 Right and left base hubs (A and B) —make 5 of each 14 4 Need 20 Need 40—2-1/2" × 6-1/2" spokes, 10—2-1/2" × 14-1/2" spokes Need 30—2-1/2" × 6-1/2" spokes Limitations and Requirements 1. Working cooperatively, students will have approximately 20 hours to construct the necessary jigs/fixtures, struts, and hubs, and then assemble the identified dome. To improve efficiency, we recommend breaking a class of secondary students (i.e., 20 students) into small groups, with one group working on the assembly jigs, one group on the struts, another on the hub parts, and so forth. 4 D Need 12 All pentagon hub spokes are at 72°. Pentagon hub (D) assemblies —make 6 of each 14-1/2 All hexagon hub spokes are at 60°. Hexagon hub (C) assemblies —make 10 of each Fig. 2—Hubs and spokes www.techdirections.com CONSTRUCTION 15 http://www.techdirections.com

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Technically Speaking Contents Direct from Washington The News Report Technology’s Past Technology Today Mastering Computers Dome, Sweet Dome—Geodesic Structures Teach Math, Science, and Technology Principles Help Students Become Wise Energy Consumers How Does FERPA Affect You? Camera Operator and Videographer e-gallery Product Central Free for the Asking More than Fun

Tech Directions - September 2007

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