More Bridges

We made two arch bridges, one with vertical supports and the other without.
Which one would be stronger?

We started adding nickles one by one. It didn't take long for the arch bridge without supports to collapse.

Then we added arch supports to the unstable bridge. One of the bridges had two supports on each side the other had one support on each side. It was amazing how many more nickles the bridge with two supports could hold.

The books on each end of the bridge are only to keep the bridge ends vertical. The paper isn't tucked under the books.