Strength in Numbers: Spaghetti Beams
IntroductionHave you ever helped your parents cook a pot of spaghetti? Strands of spaghetti are pretty long, so sometimes people break them in half so they fit into the pot more easily. How exactly does the spaghetti break? And what does this have to do with science? It turns out engineers and materials scientists study how materials break when they are bent. While professional engineers might be more concerned with steel beams in a bridge, you can still do a fun experiment with some pasta in your kitchen.
This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.
BackgroundWhat happens when you bend a piece of spaghetti (or anything else, for that matter)? Two things happen when you bend a material. Parts of it are put under tension, meaning it is being pulled apart. Other parts are put under compression, meaning it is being squished together. Certain materials tend to break more easily under either tension or compression, so it is important for engineers and material scientists to study how materials break, so they can build structures that won't break. Bridges are a great example — when cars drive over a bridge, their weight pushes downward, causing the bridge to bend. This puts the materials in the bridge in both tension and compression. Engineers have to design the bridge to make sure it can handle the weight. In this project, you will make a "beam" from bundled-together strands of spaghetti. As you hang weights from it, the beam will start to bend — putting some of the strands in tension, and some in compression. Which ones break first depends on the physical properties of pasta. Do you think pasta will break in tension or compression? Try this project to find out! Materials
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Extra: does how you bundle the strands of spaghetti together affect how much weight they can hold? What happens if you loosely tie the strands of spaghetti together with string (just enough to hold them together) vs. tightly wrapping them together with rubber bands? Extra: continue the test with larger bundles of spaghetti. You may need to use a larger container (like a bucket instead of a plastic Observations and ResultsYou should find that the strands of spaghetti towards the bottom of your bundle start to break first. These are the strands that are under tension (being pulled apart). Dry pasta is brittle, meaning it tends to break very rapidly instead of bending permanently (as opposed to a ductile material like clay, which can be stretched a lot and will change its shape before it breaks). So, when one piece of spaghetti breaks, all the other pieces might follow in quick succession. This type of brittle failure is what engineers want to avoid in structures like bridges. A rapid, catastrophic failure of a structure (like quickly snapping pasta) can be very dangerous.Cleanup
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CreditsBen Finio, PhD, Science Buddies
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Key Concepts
Materials science, tension, compression, brittle, ductile
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