DISCOVER

# How to Make Bridges for a School Project

With over half a million bridges in the United States alone, these architectural structures are a great way to help students understand a number of important concepts that range from mathematics to aesthetics. Choose a bridge type such as the steel triangle-shaped truss grid or a massive suspension bridge. Encourage students to work together in teams and create mini-structures that span faux rivers and streams. Use basic arts and crafts materials, or try reusing cardboard and plastic products for an added lesson on the environment.

Measure a one-foot section of the cardboard with a ruler. Draw two parallel lines approximately three to four inches apart with a pencil. Connect the two lines with two more lines at the ends. You will have a rectangle shape.

Cut out the rectangle.

Glue together three craft sticks to form a triangle. Place a dab of glue at each end of one stick, lay the second stick on top, end to end, at an angle. Repeat with the third stick on the other side. Connect the second and third sticks at the top with a dab of glue. Make six separate triangles, three for each side of the bridge.

Roll a thin tube of clay to fit the length of the cardboard rectangle's long sides. Place a thin line of glue on both sides of the cardboard. Firmly press the clay into the glue.

Place a thin glue line on the bottom of each triangle, one at a time. Press the glued end into the clay to hold snugly.

Connect the three triangles on each side with craft sticks glued horizontally to the top. Set aside to dry.

Measure a two-foot section of the cardboard with the ruler. Draw two parallel lines approximately two to three inches apart with a pencil. Connect the two lines with two more lines at the ends. You will have a rectangle shape.

Construct three anchorages. An anchorage is the tall structure that holds the suspension bridge's cables. Cut two craft sticks in half. Place two full-length craft sticks vertical and parallel to each other flat on the work surface. Dab two drops of glue, one on each stick, at the tops. Attach one of the half sticks horizontally, with one side on each dab. Repeat with a second and third horizontal half stick in one-inch increments, going down the length of the vertical craft sticks. Set aside to dry.

Make faux concrete blocks to hold the anchorages. Mold a square- or rectangle-shaped cube from the modelling clay. This should be at least 3-by-3-by-3 inches in size. You will need one block for each end of each anchorage.

Place two clay blocks near one end of the cardboard, two in the middle, and two at the other end with one of each pair on either side. Press the craft stick ends of the anchorages into the clay to hold firmly.

Cut two pieces of twine. Each should be roughly 30-inches long. Glue the end of each piece of twine to the first anchorage at the top. Drape the twine down towards the cardboard then up again toward the second anchorage. Glue at the top of the second anchorage. Repeat for the third anchorage.

#### Tip

Build your bridges on a flat cardboard rectangle or square. This will provide a base for easy display and mobility. Use craft or tempera paints to paint your bridge a colourful shade. Add a mock water element under the bridge by using a marker, paint or blue tissue paper.

#### Warning

Only use non-toxic arts and crafts materials that are approved for the students' ages. Supervise students at all times during the bridge-building project. Dry times for the glue may vary. Try using a small piece of tape to hold the structure together while the glue is still wet.

#### Things You'll Need

• Craft stocks cardboard
• Clear drying, non-toxic glue
• Scissors
• Modelling clay
• Pencil
• Ruler
• Twine