I Am Building A 6-Foot Diameter Sphere
Maybe I can get into the details of what my school is like some other time, but regardless, there is a Curriculum Fair coming up in May. At this fair, the entire student body’s (Pre-K to 8) work will be displayed. I’m in charge of the math area, and I have decided to display the work on gigantic three-dimensional objects (cube, pyramid, sphere for now). The solids with actual vertices will be easy but…
…the sphere is a different story. Here’s my idea, let me know what you think. I’ll take any advice or alternate plans on this. My plan involves different layers:
- 3 PVC pipes joined in a “toy jacks” sort of way for the inner foundation (one for each axis).
- chicken wire around the pipes for the beginning spherical shape.
- wire mesh netting to improve upon the large gaps in the chicken wire.
- papier mache for a smooth surface.
- some kind of sheet paper for the outer layer. Some of the work will be hung, stapled, taped, etc. to this outer layer.
Comments
it might be easier to build two half-sized, flat-bottemed identical domes and then seam them together as a complete sphere.
Get a bendable yet sturdy material (vinyl?) in strips maybe an inch wide and whatever your circumference in length. Loop a bunch end to end, interlocking them together, then stick a pin through at the very top and very bottom. Depending on how accurate your lengths are it should come out more or less perfectly spherical.
Or just buy a foam sphere from a craft store.
I think mandy’s on the right track. Think back to CS: break the problem into a series of smaller ones. Recurse. Half those domes and then quarter them. You can divvy the work up easily and fit it all together.
John said:I think mandy’s on the right track. Think back to CS: break the problem into a series of smaller ones. Recurse. Half those domes and then quarter them. You can divvy the work up easily and fit it all together.
however, breaking it down too many times will make it extremely difficult to match/patch the seams well & it may end up looking clunky.
How about forming “perfect” circles out of strips of balsa wood (or a similarly pliable material) and then interlocking them? I’m picturing that crazy amusement park ride where you sit in the middle of those concentric rings and spin on all three axes. I can’t remember what it’s called.
Gyro-something.
Jay, I need details for your idea. It sounds reasonable.
My crude idea involved drawing a 6 foot diameter circle on a big piece of paper on the ground and sort of tracing it with strips of wood to form the circles. Make a few of those and then squeeze them inside of each other, pole to pole, until you have a sphere. Does that make sense?
it’d have to be very thin balsa wood or the bisections will get increasingly indented.
Thats essentially what I meant, like lines of latitude.
Evan said:Thats essentially what I meant, like lines of latitude.
I completely missed your original post, Ev, for the record.
Jay said:I’m picturing that crazy amusement park ride where you sit in the middle of those concentric rings and spin on all three axes. I can’t remember what it’s called.
The Vomit Machine.
But as for the sphere, believe it or not, they actually make 6 foot diameter balloons. Due to their immense size, they turn out for the most part spherical. Then you can just paper mache over and pop the balloon and insert supports out a’la grade school craft project.
http://www.dealerstockroom.com/shop/?shop=1&cat=106&gclid=CIH2o_ij4JkCFctL5QodPnwSVQ
Just buy a yoga ball and call it a day.