I had an idea to teach my son (almost 4) about bridges and large structures from an engineering point of view. I thought that it would be cool to build a large bridge and put a strain gauge on it. One of those foil like strain gauges. Then I would drive some heavy LEGO cars filled w/ pennies over it and we could watch the resistance change on the strain gauge.
My question is, would it be possible to get some meaningful results out of this? I see a number of problems.
1) I've never used a strain gauge before, and I'm wondering if the pulling apart of the bridge due to the various forces is an appropriate use case for a real strain gauge. The deformations would get rather large quickly since we're working with bricks and could possibly render the strain gauge useless.
2) The introduction of the strain gauge itself, glued onto bricks radically would change the way that the forces are distributed. The strain gauge now acts as a physical support holding two bricks together.