Skeletons from Scratch: The 24 Pipe-Cleaner Challenge

By the Fifth-Grade Class of Sue LeBeau, West End School, Long Branch, New Jersey

Editor’s Note: This article showcases a classic inquiry from the Dragonfly Magazine archives, originally published in the November/December 1996 issue. It highlights the timeless power of student-led engineering and the “trial and error” of the scientific method.

The Spark

How many different shapes can you build using only 24 pipe cleaners? We wanted to know if we could build a skeleton-style structure strong enough to hold one book—or maybe even twenty! We split into five groups to design, build, and test our pipe-cleaner skeletons to see which shapes reigned supreme.

The Prediction

We all had different ideas about what would work best:

Group 1 guessed that a design wider on the top than the bottom would be stronger.
Group 2 predicted a 3D design using all 24 pipe cleaners would hold the most because it could stretch.
Group 3 thought shapes with a pointed bottom would be the winners.
Group 4 put their money on a pyramid or a flatbed to distribute weight equally.
Group 5 also predicted a pyramid, believing the strength would focus toward the center.

How We Investigated

Armed with exactly 24 pipe cleaners each, we started twisting. We came up with 79 different designs in total! To test them, we used books (like dictionaries and math texts) and weights measured in grams and kilograms. Some designs we hung weights from, while others had books piled right on top to see when the “bones” would start to bend or collapse.

Group 2 members Ben, Adam, Lauran, and Mike preparing to test their 3D stretching design.

What We Found

We had some major surprises! Many of our predictions were totally wrong, but that’s how we learned.

Group	Top Performer	Weight Held	What Happened
Group 1	Triangular Design	4.3 kg	More pipe cleaners made it stronger than the first try.
Group 2	Flat Net	99.8 kg	This was the ultimate winner!
Group 3	Internal Book Holder	0.9 kg	Pointed bottoms failed; the pipe cleaners bent too easily.
Group 4	Flatbed Design	5 kg	Weight was distributed evenly and it hardly bent.
Group 5	Unorganized Flatbed	2.72 kg	Their pyramid failed, but the flat “mess” worked!

Group 5’s cube design, which unfortunately collapsed under the weight of just one book.

Go Wild: Your Turn!

Can you beat Group 2’s record of 99.8 kilograms?

Grab 24 pipe cleaners and a stack of heavy books.
Try building a “flat net” versus a “pyramid.” Which one bends first?
Challenge: Try using different materials like straws or toothpicks. Does the “flat bottom” rule still apply?

The Field Guide (Educator Resources)

Subject/Grade Level: Physical Science / Engineering (Grades 3–6)

Inquiry Focus: Structural Integrity, Weight Distribution, and Hypothesis Testing.

The Science Behind It: This activity demonstrates load distribution. Pointed bases concentrate stress on a single vertex, causing the material (pipe cleaners) to reach its yield point quickly. Flat, woven bases or “nets” distribute the force across multiple points and members, increasing the total load the structure can handle before deforming.

Standards Connection:

NGSS ETS1.B: Developing Possible Solutions (Testing a model to identify failure points).
NGSS ETS1.C: Optimizing the Design Solution.

Materials Needed:

24 Pipe cleaners per group.
Metric scale or weights (grams/kilograms).
Heavy classroom books (Dictionaries, Textbooks).
Notebooks for sketching designs and logging data.