Sunday, May 3, 2009

Budget Science Projects: What I'm Working On

an 'almost' geodesic fort... shrink-plastic crafts from recycled takeout bag 'fabric' fusing...geometry fun with toothpicks and jujubies.

I am addicted to a website called Instructables. A place where people go and post instructions on how to make stuff.

Yesterday my kids and I made shrinky-dink jewellery from recycled take-out containers. Turns out they are made from the same kind of plastic as the Shrinkydink sheets they used to sell when I was a kid. I'm tempted to say polypropelyne...but it might be polyethylene. I spent quite a bit of time in the grocery stores reading the recycling symbols on the back of packages as I was doing my food shop. You need a number 6 or higher to get good shrinkage.

We made an assortment of beads that my daughter will turn in to necklaces.

The rest of the day was spent on building them a playhouse from recycled materials.

The Geodesic Fort Saga

Speaking of recycled plastic, I now am finely attuned to the different kinds of plastic used in plastic bags (mostly number 2 plastic...LPED).

Why, you ask? Well, because today I spent the day assembling large tarp-like sheets of plastic by heat-fusing plastic bags (in a well-ventilated area). All part of my recycled materials kiddie fort....inspired by a post on Instructables.

The basic framework is a geodesic dome made of rolled up newspaper struts. After some research, I decided to make the wall panels out of fused plastic bags. I got a little carried away collaging, and fusing on little hearts here and there. I also invited my kids to cut out shapes to fuse on to the plastic, as a way to engage them while keeping little fingers away from the hot iron, and melty plastic.

If you decide to do this project: don't make the same mistake I did. At one point, the instructions read as follows:
The topmost layer now has ten points. You now need to arrange tubes in an alternating fashion - two green from the first point, then one red, two green, then one red - all the way around.
It DOES matter which point gets the two green (long), and which point gets the one red (short).

I had a 50/50 chance...and guessed wrong...and the result is a FAR less stable structure, as the load is not carried to the floor without interruption. I have diagrams to show you what I mean. I'll try posting them below.

This is the right way to do it. The longer struts run in an uninterrupted arch from floor, across the top, and back to the floor. Yellow points represent the load.

And this is how I screwed it up. I attached the long structs to the short ones from the previous layer. The yellow dots represent stresspoints in the dome.

I'll have to go back and fix those.

A Play Fort For Less Than A Buck!

The fort is almost 8 feet in diameter, and could comfortably house both my kids and a couple of friends. Plus I got to teach my kids some lessons in geometry and save about a zillion plastic bags from the landfill.

This whole project cost me only $3.50 pesos...less than a dollar which I spent buying a copy of the Saturday National Newspaper, La Nacion to use in making the struts.

Oh, and $700.00 bucks for a new camera to replace the one my daughter dropped on the flagstones when I suggested she might like to document the building of the fort.

Right now I'm hoping that if I just put it away, the camera will miraculously heal itself-- or that it can at least be fixed.

Start with a Miniature Model

My children are 4 and 6 years old. To get them engaged in the project and help them visualize what we were going to build, we built a miniature model before we got started -- with toothpicks.

I gave them a pile of 65 toothpicks and a bag of jujubes to use to join the 'struts', and we laid out a mini model of the dome/fort on the kitchen table before we started assembling the real deal. It got them enthusiastic about helping me to build it...(ok, mostly about getting to eat the jujubes).

Let me know if you tried this.

This has been (and continues to be) a really fun and worthwhile project...and the kids will have a really great fort to play in when its all done. They're already asking me if they can sleep in it.

I'd love to know if anyone else tries building one of these, or a variation on the theme.

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