Thursday Teaching {Paper Bridges}

Project: Paper Bridges

Concept: Structures

I usually teach a unit on Bridges to my students using Dominos, followed by a project making different kinds of bridges out of popsicle sticks/balsa wood/toothpicks. If made correctly, these bridges hold some substantial weight - It's not unusual for a toothpick bridge to hold 50 lbs!

For today's experiment, we're using index cards, which won't hold quite that much weight in this configuration :)

Start with a single index card and lay it across to create your bridge. How many pennies can this bridge hold? 

When a horizontal piece is supported on either end by piers, it is a beam bridge. Ever walk across a log above a river? Beam bridge! Beam bridges rely on the stiffness of the building material.

There are three kinds of beam bridges shown here and one arch bridge.
The arch bridge was made by cutting slits on both ends of the index card and slipping those slits into the cover of the book. Try them all out and let me know how much your best bridge held!

What other bridge designs can you come up with?

Materials needed: Books, index cards, and a whole lot of pennies!

One single flat card

Lasted ~22 pennies

One folded index card

Supports a lot more weight!

Arch Bridge

Another Beam bridge