Project on 3D SHAPES

[anuami]

Hello,
My son wants to test the strength of 3D Shapes to prove which one is the strongest. (He is in 5th grade)
While brainstorming we are confused about few things
1. How do we build the hypothesis - Should we say that if a shape has more triangles then it will be able to handle more weight. He has studied in school that triangle is the strongest shape. So, he is wondering if that strength of triangle will make the 3D shapes stronger as well. He plans on testing Cube, Prism, Triangular Prism, Square Pyramid, Triangular Pyramid. Or is there any other way to prove this.
2. In terms of testing the weight it can bear - should he
(a) create sand bags of 250 gm each and stack them on the shape
or
(b) create a testing station with four columns in square, put the shape in the center, put a cardboard plank on it and put weights on the plank. Would the weight exert pressure only on the shape or will it get distributed to the columns?

Thanks
Ami.

[vysarge]

Hello anuami,

This sounds like a great, interesting project!

1. For the hypothesis, I think that would work fine. Perhaps you would want to rank them on which would hold up the most weight- as in, prism would hold up the least and triangular pyramid would hold up the most, or whichever order you decide on. That would lead to the most easily testable hypothesis.

2. For testing, I think that (a) would work the best- I think some of the weight would likely be distributed to the columns, and that the plank or columns could even give way before the shape. That might change the results- to get the best data, I'd recommend the first method.

The only concern that I have is that it seems a little difficult to stack sand bags on a pyramid; some might slide to the side, or fall off. Perhaps you could set up a small platform out of cardboard if the weights fall off?

If you still have questions or need any more help, please don't hesitate to ask!

Hope this helps,