Build an Edible Bridge

by Ann Svensen

Age: 8 and up
Time: 30 minutes or more
Type of Activity: Science/Engineering

Do your kids ever ask you how bridges work? Why they don't collapse? How much weight they can carry? Turn this fascination into a learning activity. Challenge your kids to build a bridge that can span two chairs and hold the weight of a book or magazine. Have them work together to create the lightest possible bridge that can hold the most weight.

Materials needed:

• Toothpicks or straws
• Gumdrops or mini-marshmallows
• Pencil and graph paper (optional)
• Two chairs
• A book or magazine

What to do:

Step One: Have your kids investigate the construction of things in and around the house. What kind of supports hold up the kitchen table, dining-room chairs, the roof, the mailbox? Have them build a few geometric shapes out of toothpicks and gumdrops and test them for strength. Kids will soon discover that the triangle is the strongest shape -- all three of its sides work together to support the weight you place on it.

Step Two: Some kids might like to map out how they'll build their bridge on graph paper. Others may just want to start building using the trial and error method. Either way, it's nice to have paper handy to jot down notes.

Step Three: Put the bridge to the test. Place it between two chairs and place a magazine on top. If the bridge can hold the magazine, move on to the heavier book.

Step Four: If your kids can part with their masterpieces, deconstruct and eat!

Bridge building can be as simple as joining a few marshmallows together, or as complicated as using precise measurements and mathematical theories in competition with other would-be engineers.