STEM Building and Testing a Bridge

Wednesday 15th July

I made a bridge (over a 30cm gap) that held 12.5 kg (2 stone) of books in the middle of it.

I only used cardboard, parcel tape and egg boxes (to hold it up at each end).

My plan was to attach a piece of cardboard that spanned the gap (like a road) and then cut smaller strips to put alongside at a 90 degree to stop it bending. I also put 2 pieces of tape round the middle, to stop the sides from bending outwards with the weight. I attached it all together well with tape, to hold it under the weight.

I tested the egg boxes, and realised that after 15kg, the egg boxes themselves would have crushed. Because the bridge broke at a piece of tape, I think that I should have made the tape stronger and put some tape the other way round the egg boxes to hold it better. If I wanted it to last a lot longer though, I shouldn’t have used egg boxes at all because they would have broken.

This is the video of us putting the weight on the bridge: