Toothpick and Marshmallow Bridge

The Challenge:

Design and build a load bearing bridge, using toothpicks and marshmallows, that spans the distance between two platforms (or tables) that are 6 inches apart.

• No part of the bridge can touch the table or floor between the two platforms.

• The bridge should be at least the width of one toothpick.

Test your bridge for strength by placing coins into a small container sitting on the bridge. You could also choose to hang the container from either a pencil or a straw that rests on the bridge. Note - use a lightweight container!

This challenge was adapted from Engineer Girl

Background Research:
What makes a bridge so strong? - Video from SciShowKids
Bridges - Video from BrainPop
Learn more about types of bridges here and here.
Truss bridges (the inspiration for our designs)

Tips:

1. Leave marshmallows out overnight on a tray to dry (this makes them stronger and less sticky).

2. Use toenail clippers to trim toothpicks if needed.

3. Tips for building with marshmallows and toothpicks (see steps 2 and 3)

4. When testing for strength, add 1-2 coins at a time and wait to see if the bridge holds. The bridge should hold for at least 2 seconds before adding more coins.

Alternate Challenge: Instead of building a bridge across two platforms, build one that goes up and over a bowl of water!