categories:polymers



Polymers Demonstrations

See also: Materials

Polymers are large molecules made up of repeating smaller units called monomers. This category explores how polymers form, the different types that exist, and the roles they play in natural and synthetic materials. Understanding polymers helps explain the properties of plastics, fibres, and many substances that are part of everyday life.

DemonstrationMaterialsDifficultySafetySummary
Allotropes of Sulfur★★☆★★☆★★☆When powdered sulfur is heated, it undergoes a series of changes in appearance and physical properties. Sulfur melts, becomes highly viscous as polymer chains form, then flows more freely at higher temperatures before eventually igniting. Quenching burning liquid sulfur in water produces a flexible, rubbery form of sulfur.
Bubbling Slime★★☆★☆☆★☆☆This experiment combines vinegar, xanthan gum, and baking soda to make bubbling slime. The vinegar and baking soda undergo an endothermic chemical reaction, releasing carbon dioxide gas that bubbles through the gooey slime.
‘Dissolving’ Styrofoam in Acetone★★☆★★☆★★☆When expanded polystyrene foam is placed in acetone (propanone), it appears to dissolve, dramatically shrinking in volume. This striking demonstration shows how acetone breaks down the foam structure by dissolving the polystyrene polymer, leaving only a small residue of solid polymer behind.
Instant Snow Polymer★★★★☆☆★★☆A small amount of instant snow polymer rapidly absorbs water and swells to many times its original volume, creating fluffy “snow and causing a temperature change.
Making Bakelite★★★★★★★★★Phenol and formaldehyde are mixed with a small amount of catalyst and heated to drive a condensation reaction that first forms a syrupy resol and then cures to a hard, crosslinked thermoset known as bakelite. If placed in a warm mold, the resin sets into a rigid, heat-resistant plastic part.
Making Casein Plastic★☆☆★☆☆★☆☆Heating milk and mixing it with vinegar causes the protein casein to separate and form curds. These curds can be dried and kneaded into a moldable bioplastic that hardens over time, demonstrating polymer formation.
Making Rayon Fiber★★★★★★★★★Cotton fibers are dissolved in a copper-ammonia complex solution to form a viscous liquid (viscose). When extruded into sulfuric acid, the cellulose precipitates as fine rayon fibers, simulating industrial artificial silk production.
Making Slime★☆☆★☆☆★☆☆
This classic slime recipe combines glue and Borax solution to create a stretchy, gooey substance. The process demonstrates how polymers can cross-link to form new materials, making it a fun way to explore chemistry through hands-on play.
Needle Through A Balloon★☆☆★☆☆★☆☆A balloon can be pierced with a needle without popping if the balloon is reinforced with clear tape. This works because the tape holds the stretched polymer molecules together, preventing the balloon from bursting.
Nylon Rope Trick★★★★★☆★★★The Nylon Rope Trick demonstrates interfacial polymerization, where nylon is formed at the boundary between two immiscible solutions: aqueous 1,6-diaminohexane and adipoyl chloride dissolved in cyclohexane. A continuous strand of nylon can be pulled from the liquid interface, creating a dramatic visual display of polymer formation.
Pencils Through a Bag★☆☆★☆☆★☆☆When pencils are pushed through a water-filled plastic bag, no water leaks out.
Rubber Band Stretch★☆☆★☆☆★☆☆Students quickly stretch a rubber band and feel it become warm under the nose. After the stretched band returns to room temperature, they release it quickly and feel a brief cooling. The demonstration shows the thermoelastic effect in polymers: rapid stretching aligns chains and releases heat; rapid contraction increases disorder and absorbs heat.
Sodium Alginate Worms★★★★★☆★☆☆Sodium alginate solution is extruded into a calcium chloride solution to create flexible “worms” as calcium ions crosslink the alginate chains. The rapid gelation lets you explore polymer formation, diffusion, and how soak time changes worm firmness.
Superabsorbent Polymers in Diapers★☆☆★☆☆★☆☆Disposable diapers/nappies are taken apart to discover the sodium polyacrylate polymer inside that makes them highly absorbent. By dissecting and testing the polymer, students learn how everyday products use chemistry to solve real-world problems.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff