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Make Up Your Mind
  Teaching Guide
Activity 2: Grades 5-8
Geodesic Domes

Image of geodesic dome

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  1. Did you need to use the ruler to measure the length of each tube?
    (No. The ruler was only needed to measure the lengths of one long and one short tube. These two tubes could then be used as templates from which to obtain the measures for the remaining tubes.)
  2. What was the basic geometric shape of this frame? (Triangle)
  3. What other shapes did you observe?
    (Pentagons, rhombus, hexagons)
  4. What was the maximum number of tubes that came together at any one joint?


Think About It
How would increasing the number of component triangles affect the shape of the dome?
(The more triangles that are used, the closer the shape resembles a true sphere.)

Small Scale Model
The plans for building a geodesic dome are scalable. In fact, you can use the steps above to build versions using either plastic straws or wooden toothpicks. Suppose you needed to scale the measurements to straws that are 20 cm long. If you opted to use the uncut length of the straw as the longer rod, what length would the shorter one need to be cut to? Explain.
(Using the ratio 26:24, we uncover a proportionality constant of about 0.92. When you multiply the 20 cm length by the constant, you arrive at a length of about 18.5 cm for the shorter support.)

Geodesic Dome Advantages
Geodesic Dome Advantages
Compare and contrast a geodesic dome design with a more traditional dome built from reinforced cement. Think about the advantages of the geodesic style. What are the advantages in material simplicity?
(You need only three basic parts: two lengths of pipe and a connector.)
What are the advantages in illumination?
(The open frame allows daylight to spill into the dome)
What are the advantages in placing and lifting supports?
(The basic parts of the dome are relatively light)


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