Materials Demonstrations

See also: Polymers

Materials science examines the properties and uses of the substances we rely on, from natural resources to modern synthetic products. This category looks at what makes different materials suitable for particular purposes, and how their characteristics can be explained by their structure. Studying materials links science to design, technology, and engineering.

Demonstration	Materials	Difficulty	Safety	Summary
Angle of Repose	★★☆	★☆☆	★☆☆	This experiment determines the flow characteristics of powders by measuring the angle of repose—the steepest angle at which a material can rest without sliding. Sand samples of different particle sizes and moisture contents are poured to form heaps, and the angle of each heap is measured to evaluate how size, shape, and cohesion affect powder flowability.
Annealing and Quenching Bobby Pins	★★☆	★☆☆	★★☆	This demonstration shows how heating and cooling rates affect the properties of steel. By comparing annealed and quenched bobby pins with an untreated one, students can observe changes in hardness, flexibility, and brittleness that result from different heat treatments.
Ball and Ring Expansion	★★★	★☆☆	★★☆	This demonstration shows the thermal expansion of metals. A metal ball can pass through a ring at room temperature, but when heated, it expands and no longer fits. Cooling the ball in water allows it to contract and pass through again.
Bimetallic Strip Thermostat	★★☆	★☆☆	★★☆	This demonstration uses a bonded copper–steel strip to show how temperature changes cause mechanical movement. Because the metals expand at different rates when heated, the strip bends, illustrating the principle of differential thermal expansion. This effect underpins many real-world devices, such as thermostats and circuit breakers, where heat is converted into mechanical motion for control purposes.
Heat Conduction of Different Materials	★★☆	★★☆	★★☆	This demonstration shows how heat conduction varies in different materials by using rods of copper, iron, and glass. Wax is used to attach small nails to the ends of the rods, and the heat from a Bunsen burner causes the nails to drop off in the order of conductivity.
Forensic Fiber Analysis	★★☆	★☆☆	★☆☆	Forensic scientists analyze fibers from crime scenes using tests such as burn analysis and polarized light microscopy. These methods reveal whether a fiber is natural or synthetic and help investigators narrow down suspects without destroying evidence.
Gallium and Aluminium Can	★★★	★☆☆	★★☆	When liquid gallium is applied to an aluminum can, it penetrates the aluminum’s grain boundaries and disrupts its crystal structure, making the can brittle and easy to puncture.
Hydrophobic Coatings	★★☆	★☆☆	★☆☆	This demonstration shows how hydrophobic coatings prevent water from soaking into a surface. By applying a water-repellent spray to sand or using wax crayons on paper, students can see how water beads up and rolls off instead of being absorbed.
Freezing a Bouncy Ball in Liquid Nitrogen	★★★	★★☆	★★★	A bouncy ball submerged in liquid nitrogen loses its elasticity because the extreme cold freezes its rubber molecules into a rigid, brittle structure. As a result, the ball cannot compress and rebound, making it unable to bounce until it warms up again.
Magic Sand	★★★	★☆☆	★☆☆	Magic sand is ordinary sand coated with a hydrophobic substance that prevents it from mixing with water. When placed in water, it clumps together and forms shapes like towers or cakes, while remaining perfectly dry when removed.
Magnetic Shielding	★★☆	★☆☆	★★☆	This demonstration explores how different materials affect magnetic attraction. By placing objects between a magnet and a paper clip, you can observe which materials allow magnetic fields to pass through and which ones block or redirect them. It illustrates the concept of magnetic shielding and the behavior of magnetic field lines in various materials.
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.
Melting Gallium in Your Hand	★★★	★☆☆	★★☆	Gallium, a metal with a melting point of 29.76 °C (85.6 °F), can melt in the palm of your hand. The demonstration shows how body heat is enough to turn solid gallium into a silvery liquid.
Metal Rod Conduction	★★☆	★☆☆	★★☆	A metal rod is heated at one end, and pieces of wax attached along its length melt one by one. This demonstrates how heat is conducted through the solid from the hot end toward the cooler end.
Nitinol Shape Memory Alloy	★★★	★☆☆	★★☆	Nitinol, a nickel-titanium alloy, demonstrates shape memory by returning to a pre-set shape when heated. Unlike ordinary wire, Nitinol “remembers” its original form and straightens itself when exposed to sufficient thermal energy.
Paper Recycling	★☆☆	★☆☆	★☆☆	This activity and explanation show how paper is recycled, both industrially and at home. Paper fibers can be broken down into pulp, cleaned, and re-formed into new paper products, reducing the need for tree harvesting and helping conserve natural resources.
Pencils Through a Bag	★☆☆	★☆☆	★☆☆	When pencils are pushed through a water-filled plastic bag, no water leaks out.
Popsicle Bridge	★☆☆	★☆☆	★☆☆	Build and test model bridges of different designs (for example, truss types made from popsicle sticks or plastic straws) by gradually applying a load until failure, then compare performance using strength-to-weight ratio. This demonstrates how design, materials, span, and joints influence a bridge’s ability to carry weight.
Properties of Covalent, Ionic and Metallic Substances	★★☆	★★☆	★★☆	This experiment compares the physical properties of covalent, ionic, and metallic substances by observing their appearance, luster, solubility in water, melting point, and electrical conductivity. By analyzing differences, students can infer the type of bonding present in each substance.
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.
Rubber Chicken Bones	★☆☆	★☆☆	★☆☆	Clean chicken bones are soaked in vinegar so the acid reacts with calcium carbonate in the bone, removing minerals and leaving the collagen matrix flexible. After drying, the bones can harden in their new shape.
Simple Heat Conduction Experiment	★☆☆	★★☆	★★☆	This experiment compares how well different materials - metal, wood, and plastic - conduct heat by observing how quickly butter melts on each spoon after being heated in boiling water. The results demonstrate that metals conduct heat much more effectively than wood or plastic.
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.
Strength of Paper Columns	★☆☆	★☆☆	★☆☆	Different column shapes and sizes made from regular paper can support weight. By stacking books or weights on each shape, students can discover which structure distributes force most effectively and holds the most weight.
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.
Testing Material Properties	★☆☆	★☆☆	★☆☆	Students investigate basic properties of common materials by observing, folding, crinkling, tearing, stretching, and then strength-testing strips of paper, plastic, and aluminum foil. The class emphasizes planning fair tests so each material is tested the same way.
Thermochromic Materials	★★★	★☆☆	★☆☆	Thermochromic materials are substances that change color with temperature. They are used in novelty items, clothing, toys, and scientific demonstrations, allowing students to see a physical property that responds directly to heat.
Turning Copper Coins Silver and Gold	★★★	★★★	★★★	Copper coins can be plated with zinc, giving them a silver appearance. Heating the zinc-coated coins in a flame causes zinc and copper to alloy, forming brass, which gives the coins a gold color.
Uncrushable Egg	★☆☆	★☆☆	★★☆	In this demonstration, participants attempt to crush an egg by squeezing it in their hand. Despite applying strong force, the egg does not break when the pressure is evenly distributed. However, uneven pressure, such as pressing on one side or squeezing with a ring on, causes the egg to crack.

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