S.T.E.M. Activity | Building A Truss Bridge

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S.T.E.M. Grape & Toothpick Truss Bridge Building Activity

Today we will be doing a stem activity!

You Will Need

  1. Grapes
  2. Craft sticks
  3. Toothpicks

Before we start building our bridges we will have the kids discover which is stronger triangles or squares.

  • Build a 6in structure using a cube design with grapes and toothpicks.
  • Next build a 6 inch tall structure using a pyramid design. Wiggle both structures, which is stronger?

That’s right the pyramid is stronger! A square tends to collapse by giving way at their joints, their weakest points.

How to Build A Truss Bridge

A truss bridge combines triangles and squares.

  1. Build one side of your truss bridge using a triangular pattern.
  2. Repeat for the other side.
  3. Bring the two sides together and connect each point with a toothpick that will form your squares.

Congratulations you just built a Truss bridge!

We will add craft sticks to our bridge so trains can cross our bridge.


This activity is great for improving fine motor skills and cognitive development. Also, Children who have an early exposure to stem activities do better in math and science.

Fun Fact

Here’s a cool fact for you…Truss bridges were designed in the late 1800’s. When trains became a popular way to ship goods. It was a bridge that was strong enough to stand up to the train’s weight.

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