# Hands-on Activity: Spaghetti Bridge

### Summary

Civil engineers design structures such as buildings, dams, highways and bridges. Student teams explore the field of engineering by making bridges using spaghetti as their primary building material. Then they test their bridges to see how much weight they can carry before breaking.

### Engineering Connection

Many people in different branches of engineering work to build bridges. Civil engineers are responsible for design and construction of such structures, however they also work with mechanical engineers and material engineers to design the most stable structures. These engineers must consider many variables when creating plans, such as the distance to be spanned, where the bridge is being built, the expected type of traffic it will have to withstand, materials available, budget and what the bridge will look like.

### Educational Standards

•   Common Core State Standards for Mathematics: Math
•   International Technology and Engineering Educators Association: Technology
•   Massachusetts: Science
•   Next Generation Science Standards: Science

### Learning Objectives

• To create a design method.
• Group work and discussion.
• Building techniques that civil engineers use.

### Materials List

• 1 pound dry spaghetti
• glue gun
• glue sticks, 1 package
• various weights from 5 to 50 pounds
• large tub (or newspapers to spread out), to make clean-up easier
• 2 tables (place 1 foot apart)
• metal strip (to serve as the road)
• chain (to hold the weights)

### Introduction/Motivation

Who do you think creates the human-made structures in our town? Who makes sure they are safe for us to use? (Listen to student ideas.) It is civil engineers who design and create structures such as buildings, dams, highways, skyscrapers and bridges.
We can explore the field of engineering by making bridges. We can then test them by applying weights to see when they break. Let's get started!

### Procedure

1. Show students the available "building materials," including the metal strip "road," chain and weights that will be used for testing.
2. Divide the class into teams of students.
3. Have teams draw their bridge designs on paper. Make sure that bridges are long enough to span a specified distance between two tables.
4. Create the bridge using hot glue to hold it together.
5. When the bridges are complete, test their strength. Place a bridge so it spans across the gap between two tables. Place a tub or spread-out newspapers under the bridge to catch falling debris and make clean-up easier.
6. Put the strip of metal on the bridge (as the road). Then apply weights on the chain, starting with 5 pounds and working up to 50 pounds, or until the bridge breaks.
7. Conclude with a class discussion to compare results and draw conclusions. Use the Investigating Questions as a concluding assessment.

### Safety Issues

• Be careful not to get burned from the hot glue and hot glue guns.
• Wear safety glasses.
• Beware of falling weights.

### Investigating Questions

• What happened when you added more weights? What does the bridge look like?
• Does adding more height to the bridge make it stronger?
• What are some ways to improve your design?

### Assessment

Assign the Investigation Questions as a test, quiz or homework. Review students' answers to gauge their comprehension.
Have students record how much weight their bridges withstood before they failed. Then, as a class, create a histogram showing how much weight each bridge held. Discuss which design was able to carry the most weight and why (materials, geometry, use of glue, etc.).