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Carnegie STEM Girls: Toothpick Tower

Your Challenge: Build a Cost Effective Structure.

Materials:

Toothpicks

Gum Drops

Scale

Here’s How:

PART 1: Building Geometry: Squares, Cubes, and Pyramids

In order to build a weight-bearing structures, we need to explore the different geometries and how good and/or bad they are as building elements.

1. Using 4 toothpicks and 4 gumdrops, build a square.  Lay this square on the table and then stick 1 toothpick in each gumdrop, sticking straight up.  Top each of these toothpicks with a gumdrop and connect these 4 gumdrops with toothpicks.  You have now built a box.

2. Now you will build a pyramid.  Using 3 toothpicks and 3 gumdrops make a triangle and lay this on the table.  Now stick 1 toothpick in each of these gumdrops, sticking straight up.  Take these 3 toothpicks, bend them into the center and connect the 3 toothpicks with 1 gumdrop.  You now have a pyramid.

3. Gently press on the box and the top of the pyramid.  What happens to each shape when you press on the top?  Does the structure keep its shape?  Does the structure collapse?

4. Based off of your observations, which shape is better for building structures: squares or triangles?

PART 2: Designing and building a weight-bearing structure

Design Parameters:

Gumdrops may not be cut or altered

Toothpicks cannot be cut or altered

The structure must be able to have weight balanced on the top

The structure must be movable

No initial testing of the structure is allowed

The weight must be held for 5 seconds

Every gumdrop and toothpick costs a hypothetical \$10

Design and build a structure that will bear the most weight.  The ‘winning’ structures will be the weight-bearing structure that is the most cost-effective weight.

 Cost Points Cost Points Cost < \$200 50 Cost < \$250 45 Cost < \$300 40 Cost < \$350 35 Cost < \$400 30 Cost < \$450 25 Cost < \$500 20 Cost < \$550 15 Cost < \$600 10 Cost < \$650 5

Every brick that the structure can hold is worth 20 points.

The tower that earns the most points is the winner.

PART 3: Designing and building the tallest weight-bearing structure.

You will now use your toothpicks and gumdrops to build the tallest building that will hold a brick of weight for 5 seconds!

Fun Facts:

• Maine is the largest producer of toothpicks in the world, producing 90% of toothpicks used in America daily.
• A man once built a model of the Eiffel Tower out of toothpicks, which rose to 23 feet!
• In the 17th century, toothpicks were used by the upper class and created from gold.
• A man once made a 100,000 toothpick structure of San Francisco.

Related Careers:

Middle School, High School

## Organization

Carnegie STEM Girls

Tutorial