Half term fun – building a geodesic dome
Posted by markharrison on October 21, 2007
It’s half term this week, which of course causes a few problems (because there are one or two things business-related I’d hoped to finish), but has many joys (because I can just take a few days out to spend with them.)
Anyway, on the list of things to try with a little girl keen on maths was building a Buckydome / geodesic dome.
I found a great site that had an on-line calculator for the lengths of “struts” I needed. The site is run by a Californian maths teacher, who uses the summer holidays to build these domes for Americans to use as shade shelters, particularly at the Burning Man festival.
We weren’t intending using this as a shade shelter, just a fun thing to do, so rather than making the dome out of metal piping, we used A4 paper (reduce, reuse, recycle.)
We made a “2V” dome. The dimensions we decided on ended up with the “short side” of an A4 sheet of paper being the “B”strut at 21cm, so up I rolled 30 pieces of A4. That meant that the “A”strut 23 3/4 cm long… so sure enough, Mary cut 35 sheets to size, and we rolled them the “long” way.
The resultant structure is very wobbly during construction, and then just tightens up, as if by magic, at the end of the build.
In fact, it was (just) big enough for Mary (age 34) to curl up in (see picture!). Pippy (age 5) got involved, and helped roll the paper at first… but then preferred a game of counting how many struts we’d made, and substracting to work out how many were still to go.