Get Slimy: Exploring Matter One Stretch at a Time
Students design slimeCopyright Ester Abellon/Maricel Gavis
Students become materials engineers tasked with designing and optimizing a functional polymer-based material (i.e., slime) through systematic testing and iteration. They begin by making a control slime and collecting quantitative and qualitative data on key material properties, including stretch length, bounce height, and texture. Through repeated trials and averaging results, students analyze variability and identify relationships between composition and performance. Students then apply this analysis in an engineering design challenge, where they select performance criteria and redesign their slime to meet specific functional requirements. They iterate based on experimental data, evaluate trade-offs between competing properties, and refine formulations accordingly to optimize material performance for a defined application.
Materials engineers focus on understanding and controlling how materials behave by linking structure at the molecular level to performance at the macroscopic level. In polymers, they study how long chains of molecules interact, how those chains are connected through processes such as cross-linking, and how these connections influence properties like strength, flexibility, and durability. Materials engineers are also developing more sustainable alternatives to traditional plastics, including packaging materials made from natural polymers such as casein (a protein found in milk), which can break down more easily in the environment. Just like in the slime investigation, they test how new materials form and evaluate properties such as strength, flexibility, and durability. By studying slime, students practice the same kinds of observations and data-driven decisions engineers use to design safer, more sustainable materials for real-world problems.
After this activity, students should be able to:
- Model the structure of matter by explaining how glue polymers and borax interact at the molecular level to form a new substance.
- Gather and analyze data on the physical properties of slime, such as bounciness, stretchiness, and texture, and relate them to the proportions of materials used.
- Identify and explain evidence of a chemical reaction by observing how the mixture changes from a liquid to a stretchy, solid-like material with new properties.