Spaghetti and marshmallow tower
Summary
Degree programs
Research themes
This activity is part of our Science Lab series. Check out the ANU Science Lab for more experiments! In this activity, you will build a tower using spaghetti and marshmallows. You will investigate how engineers use geometry to create strong structures and discover why diagonal bracing can make a tower more stable. Watch the video above to see how it is done.
Materials
For this activity, you will need:
- Uncooked spaghetti strands
- Marshmallows (mini or standard size)
How to build the tower
Step 1: Build the base
- Use marshmallows and spaghetti to create a square base.
- Make sure all sides are approximately the same length.
- Check that the structure can stand upright.
Step 2: Build the tower
- Insert vertical spaghetti strands into each corner of the base.
- Connect the tops of the vertical strands with additional spaghetti to form a cube-like frame.
- Continue building upwards if you would like to make a taller tower.
Step 3: Add diagonal supports
- Add spaghetti strands diagonally across the sides of the tower.
- Continue adding diagonal supports until each face contains triangular sections.
- Observe how the structure becomes more rigid as additional bracing is added.
Step 4: Test the tower
- Gently push the tower from different directions.
- Observe how well it resists bending and twisting.
- Compare a tower with diagonal bracing to one without diagonal bracing.
How does it work?
A simple square frame can easily change shape when a force is applied. For example, a square can be pushed into a diamond shape without changing the length of its sides. This makes square frames less stable on their own. Adding diagonal supports changes this.
The diagonal spaghetti strands divide the square faces into triangles. Triangles are one of the strongest shapes in engineering because they cannot change shape without bending or stretching one of their sides.
In this activity:
- The spaghetti strands act as beams.
- The marshmallows act as joints connecting the beams.
- The square frame provides the overall shape of the tower.
- The diagonal supports create triangular sections that strengthen the structure.
When a force is applied to the tower:
- The load is shared between many spaghetti strands.
- The forces are distributed throughout the structure.
- The diagonal supports help prevent the tower from twisting or collapsing.
- The tower becomes stronger and more stable than a frame without bracing.
Engineers use similar designs in real-world structures such as bridges, cranes, electricity transmission towers and tall buildings. By combining simple shapes into larger frameworks, they can build structures that are both lightweight and strong.
Although a triangular pyramid is one of the most efficient shapes for distributing forces, practical structures often need square or rectangular bases. Adding diagonal bracing allows these structures to take advantage of the strength of triangles while still providing useful interior space and a stable footprint.
Science fair project: Take it further
Once you have built your tower, investigate how different design choices affect its stability.
- Compare a tower with diagonal bracing to one without diagonal bracing. Which is stronger?
- Test square, rectangular and triangular bases. Which design provides the greatest stability?
- Stack multiple cube units on top of one another. How tall can you build before the structure becomes unstable?
- Compare fresh marshmallows with marshmallows that have been left out overnight. How does joint stiffness affect tower strength?
- Add small weights to the top of the tower. How much mass can the structure support before collapsing?
- Create a table to record your observations. Which design was the strongest? Which design used the least amount of material for the greatest stability?
Enjoyed this experiment? Explore more hands-on activities on the Science Lab ANU YouTube channel.
